Welcome back to Ranking Files, an ongoing Mandatory Monday feature that rates the NFL's best and worst units. It has come to my attention that most of you are either watching soccer or preparing for some Independence Day weekend rowdiness, so this is as good a week as any to bury (Cover! I meant cover!) the special teams.

We know that the Seahawks secondary will be awesome this year and that the Broncos receivers will not suddenly forget how to get open and catch footballs … unless they are facing the Seahawks secondary. Most units don't fluctuate much from year to year without an obvious explanation, like a salary cap purge or injury rash.

Special teams success, however, varies widely from season to season without warning. A great kicker could go 8-of-9 on 50-plus yarders one year, 1-of-5 the next, and then bounce back to 2-of-3 the third year, with no injury to explain the streaks or slumps (those numbers were taken from Morten Andersen, 1995-97). A star returner can go two years without a touchdown, then suddenly produce two or three (see Devin Hester's career). Coverage units collapse during injury crises at linebacker or other positions: Suddenly the best punt gunner is starting on defense, the kid from the practice squad is chasing returners and disaster ensues. Variables you rarely think about can skew statistics for the entire league: The East Coast snowstorm of Week 14 last year affected offensive and defensive stats a little bit, but it caused special teams havoc as kickers took the week off and returners speed-skated for touchdowns.

That was a long way of saying that more guesswork went into these special teams rankings than the evaluations of any other position. To filter out all the random noise, teams that have had quality kick and punt units for several seasons got a boost over teams that suddenly found a hot kicker last year. I also focused on factors that don't fluctuate much, including one that is rarely talked about beyond Football Outsiders circles: kickoff distance. Field goal percentages rise and fall, but kickoff lengths do not. Graham Gano produced 63 touchbacks and just 16 returnable kicks last year, forcing opponents to face the Panthers' front seven from the 20-yard line on drive after drive. The Panthers did not make this week's lists, but that's no fault of Gano, the team's secret weapon.

Special teams are usually an afterthought for fans and writers, but they can sometimes serve as a bellwether of organizational health. When special teams are rocking, it usually means that the scouting department is providing tons of backups who can block and tackle, that the franchise has the resources to invest in specialists and so on. When they stink, it sometimes means that the organization is too busy cobbling together starters to worry about the kicking game, or too screwed up to find and develop the players they need. It's not a perfect correspondence, but perennial powerhouses are well represented in our top five, while the bottom five is heavy with permanent rebuilding projects.

The Five Best Special Teams

1. Baltimore Ravens

Kicker Justin Tucker and returner Jacoby Jones made massive contributions to the 2012 Super Bowl run. Tucker, then a rookie, was 14-of-17 from 40-plus yards while blasting kickoffs through the end zone. Jones delivered three regular-season return touchdowns and a fourth in the Super Bowl. Last year, they kept the Ravens on the playoff fringe when the team had no business staying in the field. Tucker won the Lions game almost single-handedly (53- and 61-yard fourth-quarter field goals), did most of the scoring in the Week 13 Steelers victory (five field goals), and kept the Bears game competitive with his talent for bending field goals around Sharknados. In between those games, Jones skated for a touchdown in the snow to help spark a wild win against the Vikings.

Ozzie Newsome and John Harbaugh maintain a coursing pipeline of developing prospects, so there are always bench players with a year or two of experience available for the blocking and coverage units. Albert McClellan (11 teams tackles) and Anthony Levine (10) are among the familiar faces who will keep the coverage teams reliable this year. Tandon Doss, who returned a punt for a touchdown last year, is now in Jacksonville, but the Ravens have gotten fine production from Lardarius Webb and other returners in years past. It's a sign that Harbaugh, a longtime special teams coordinator, does not need any one particular player to keep the kicking games solid.

2. Seattle Seahawks

Seahawks opponents gained just 82 yards on punt returns last season. They averaged just 3.9 yards per return, the second lowest figure in the NFL, but that tells only part of the story. Opponents waved for 30 fair catches while returning just 21 punts. So opponents really averaged just 1.6 yards per returnable punt, slightly less yardage than the typical adult male could gain by catching the ball and falling forward.

Punter Jon Ryan adjusted his style in 2013 in a conscious effort to eliminate returns. He started kicking end-over-end full time, producing high hang times and tricky-to-field punts instead of 60-yard blasts. The results were a minor decrease in the gross but a significant increase in the net. Of course, it also helps that guys like Kam Chancellor and Earl Thomas play special teams whenever needed, supporting gunners like Jeremy Lane (12 teams tackles).

Kicker Steven Hauschka is reliable. A little bit of Percy Harvin goes a long, long way. Harvin is listed as the two-way return man right now, but it is more likely that Jermaine Kearse and others will handle regular duties, with Harvin waiting for someone to pull the fire alarm.

3. St. Louis Rams

Remember how the Seahawks allowed just 3.9 yards per return and produced 30 fair catches? The Rams allowed just 2.6 yards per return, with 23 fair catches. Johnny Hekker is a fine punter, and the Rams coverage units had a knack for forcing fumbles in 2013.

Greg "the Leg" Zuerlein is one of three great kickers from the rookie class of 2012 featured in our top five. (Tucker is the best of the bunch, the third is coming soon.) Zuerlein earned his nickname with a series of dramatic 50-yarders as a rookie, but he was just 1-of-2 on 50-plus-yard field goals last year, because fluctuation happens. Two-thirds of Zuerlein's kickoffs resulted in touchbacks, however, so he is still The Leg when pinning opponents deep. Tavon Austin recorded a 98-yard punt return last year, and there is more where that came from.

If the Rams cover punts better than the Seahawks, get more mileage from kickoffs than the Seahawks and employ both a young-gun kicker and a dangerous returner, why do they rank behind the Seahawks? First, Austin's 98-yarder accounted for 35 percent of his punt return yardage for the year. Austin produced too many one-yard punt returns and sub-20-yard kickoff returns. Second, forcing fumbles on returns is not the kind of skill that transfers from year to year. Third, Hekker and Zuerlein have the advantage of playing in a dome. Throw in the fact that one team strutted its stuff in the Super Bowl and the other didn't, and the Seahawks win a close race.

4. New England Patriots

Stephen Gostkowski booted 65.7 percent of his kickoffs for touchbacks last year, the fourth-highest percentage in the league. Those that got returned were taken just 20.8 yards, tied for the sixth-lowest figure in the league. Gostkowski also went 5-of-6 from 50-plus yards, but the Patriots don't want to ask him to kick as many 50-yard field goals. They want him kicking off deep, after extra points.

Coverage is the name of the game for the Patriots special teams. Opponents averaged just 7.6 yards per punt return, with a long return of just 23 yards. Longtime gunner Mathew Slater (29 solo tackles in the last three years) stays on the roster despite wide receiver emergencies specifically to keep the coverage teams strong. Nate Ebner and Chris White have joined him as professionals on the kick units.

Julian Edelman is a reliable punt returner with some big-play ability. He had a quick trigger on the fair-catch button last year, but that will happen when you are also the leading receiver. The Patriots were docked a few slots for not having a kickoff returner at the moment. Slater is listed atop the depth chart, but he has not practiced much in the offseason. Reggie Dunn fielded kicks during minicamps but was recently waived. There are lots of other candidates (rookie James White returned some kicks at Wisconsin and looks the part, Devin McCourty handled the chores in the past, Josh Boyce returned a few last year, there are scads of undrafted skill-position rookies) but until the Patriots sort things out, they must settle for fourth place.

5. Minnesota Vikings

The Vikings gave up a whopping 27.1 yards per kickoff return last year. Part of the problem was facing Jacoby Jones in a Winter Classic. Part of it was Devin Hester denial, as Hester had a string of long returns against the Vikings last season. Part of the problem was that the coverage units were not so good. After Larry Dean (12 tackles) and Robert Blanton (10), there were too many guys standing around looking to get blocked.

On the flip side, Cordarrelle Patterson is one of the NFL's brightest young return stars, Marcus Sherels is a boom-or-bust returner with a lot of boom and the Vikings blocking units were as good last year as the coverage units were weak.

The Leslie Frazier Vikings had a fetish about H-backs, you see. Some teams carry an extra wide receiver, some make room for a pass rush specialist, others are happy to employ a kickoff-only kicker. The Vikings liked their H-back depth chart to run about 20-deep. Jerome Felton. Rhett Ellison. Allen Reisner. Chase Ford. Matt Asiata was essentially an H-back before Adrian Peterson got hurt, forcing him to take handoffs. If your roster is full of 240-pound blockers who can run a little bit, it stands to reason that your kickoff blocking will be deadly, while your coverage units run the risk of getting left in the dust.

Most of the H-backs are still on the roster, as are Blanton and Dean, but Hester is no longer in the division to cause two problems per year. Kicker Blair Walsh tailed off after his magnificent 10-of-10 performance from 50-plus yards as a rookie, but he is still the third of the NFL's three bright young kicking stars. Patterson's tackle-breaking ability makes him unique among returners: He can produce big plays even when the blocking is ordinary. The Vikings will remain dangerous to opponents on special teams this year, and they should not be as likely to endanger themselves.

Worth Mentioning

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Andy Lee and Phil Dawson form one of the NFL's best punter/kicker combinations. (USA TODAY Sports)

Top 10: San Francisco 49ers. As repeated often this week, long field goal percentages fluctuate. If a kicker goes 5-for-5 from 50-plus yards, it could be a sign that he has a "big leg," or he could be an average NFL kicker benefitting from ideal circumstances: five 50-51-yard kicks in perfect weather, with perfect snaps and holds, from the proper hash mark, in low-pressure situations, etc. If he goes 1-of-6 the next season, well, maybe three of those kicks were 58-yarders before halftime in Buffalo, Chicago and Green Bay in December, and he just didn't hit two others exactly right.

But what if a kicker goes 18-of-21 over three seasons? And what if that kicker is a veteran who has always played in tough outdoor cities? If I needed one kicker to deliver a 50-yarder in a windy drizzle to win a game, I would probably pick Justin Tucker. If he wasn't available: Phil Dawson.

Dawson doesn't have a deep kickoff leg, but he delivers them high, and the Niners coverage units have been awesome throughout the Jim Harbaugh era. The Niners take coverage and blocking units seriously. C.J. Spillman has 33 special teams tackles in the last three years. Lifetime special teamer Kassim Osgood made the roster last year, despite the Niners' obvious need for receivers during the first half of the year. Osgood recorded seven special teams tackles, recovered a fumble and blocked a punt against the Seahawks.

Andy Lee may be the NFL's best punter right now. So why are the Niners yet again stuck among the honorable mentions? It's LaMichael James. He looks like a dangerous returner, but his longest kickoff return last year was 41 yards, and he has not shown much on punts. Perhaps it's all those Hekker boomers and Ryan end-over-enders he has to field, but on a team with such attention to kicking detail, high-impact returns should be more common.

On the Rise: Atlanta Falcons. Devin Hester can still kill you with a big return. Hester looked much more comfortable last year when the Bears stopped making him pretend he was a slot receiver, so the Falcons' decision to design a Hester offensive package might be a step in the wrong direction. The "Hester package" looks like a bunch of screens, reverses and decoys right now, however. It's not like he is trying to learn a Mike Martz playbook. So Hester should still be able to commit body-and-soul to what he does as well as anyone in NFL history.

Hester upgrades some decidedly mediocre return units, while the legions of youngsters competing for starting jobs on defense should shake out some aggressive coverage squads. The kicker and punter are fine. From the not-so-random factoid department: punter/kicker-offer Matt Bosher was 3-of-6 on onside kicks last year. The Falcons had one onside kick play (against Arizona) in which Bosher putted the ball straight ahead and flopped on it himself while two teammates blocked for him. They had another (against the Niners) in which Bosher wedged the ball 20 yards downfield at a 45-degree angle; Jason Snelling raced past the first row of blockers to pounce on it. The fact that Bosher has so many clubs in his bag and the Falcons have an entire playbook of onside kick wrinkles is a sign that there is more to their 3-for-6 performance than statistical variance. Opponents should be alert on kickoffs this year.

Hard to Classify: Denver Broncos. Altitude makes a huge difference on kickoff and punt statistics. Matt Prater finished second to Graham Gano in touchback percentage while booting a whopping 81 touchbacks (he kicked off a lot), but kickoff returns are rare for both teams at Mile High. When Prater's kicks come up short, the Broncos coverage teams have had a habit of getting caught off guard at the worst possible moment in the last two years.

Trindon Holliday made up for his teammates' coverage lapses by producing plenty of long returns, but Holliday is now with the Giants. Wes Welker is currently listed as the punt returner, and we all know he can do it. But should he do it? Backup safety Omar Bolden is listed as the kickoff returner, though there are lots of candidates, including undrafted rookies Brennan Clay and Bennie Fowler. At least the Broncos still have a Colquitt punter, though he is the second-best Colquitt punter. (Chiefs fans take note: you made the top 10, but I just don't feel like writing about knuckleball punts when golf-analogy onside kicks are available.)

From the Ashes: Washington Redskins Dan Snyder does not understand the concept of special teams. The whole idea of valuable low-priced specialists is as alien to him as the concept of subtle, sophisticated beauty is to reality television starlets. If he has the choice between retaining a) a fifth wide receiver who can record a dozen tackles on punts, block for returns and field a return or two himself in a pinch, or b) two 38-year-old receivers for $3-million each who made the Pro Bowl eight years ago, Snyder will go for the Joey Galloway gang every time. Kickers, meanwhile, are usually acquired with leftover cap money, which is equivalent to Snyder's pocket change.

Since 2000, the Redskins have finished 30th or worse in Football Outsiders' special teams ratings three times and 25th or worse three other times. They have not finished higher than 21st since 2007, which is distressing: Bruce Allen began reining in Snyder back in 2009, but the situation has actually gotten worse. By last year's crater situation -- four return touchdowns, a miserable season by punter Sav Rocca, two kickers, Santana Moss fielding punts at age 73 -- Mike Shanahan's Napoleon complex was probably more to blame than Allen or Snyder's mistakes. No matter the cause, the Redskins teams were a disaster.

Veteran Robert Malone and prospect Blake Clingan are now competing to replace Rocca. Kicker Kai Forbath is healthy after missing part of last year with a groin injury, with seventh-round pick Zach Hocker around to prove that the Redskins are serious about making upgrades. The return situation is still a problem -- there have to be better solutions than Moss and Niles Paul -- but the Redskins signed professional specialists Adam Hayward and Akeem Jordan to stem the tide of long returns. In other words, if you want Snyder to act, give him someone to throw a check at.

These are not great special teams, but at least they are no longer neglected.

From the Ashes: New York Giants My "special teams health indicates organizational health" hypothesis gets plenty of support from the 2013 Giants. Special teams contributors from the 2011 Super Bowl run, like Mark Herzlich and Spencer Paysinger, were torn between kick coverage and the starting lineup. With the Giants grabbing last-ditch running backs off the waiver wire, they had no hope of acquiring a quality returner. Injuries and confusion led to three punt return touchdowns early in the season, while the combination of Reuben Randle, Jerrel Jernigan and Michael Cox did nothing of interest on returns.

Trindon Holliday's arrival solves the return problem, and the Giants were already restoring law and order on the coverage units by season's end. Early in last season, Damontre Moore (who made himself useful on special teams with a blocked punt) could be seen lined up as a kick gunner on the wing, with reserve tight end Larry Donnell on the other wing. No wonder Dexter McCluster sliced through the first line of defense: The Giants were just throwing the best available healthy bodies at a bad situation. Later in the year, suitable youngsters like Cooper Taylor took over as gunners, and the long returns became less frequent. With some free agent arrivals and lots of rookies, the current roster is deep enough to keep the Giants from doing desperate stuff like make 250-pound pass rushers race up the sideline.

The Five Worst Special Teams

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Travaris Cadet may be tasked with replacing Darren Sproles in the Saints' return game. (USA TODAY Sports)

28. New Orleans Saints

Sean Payton has a mental block about kickers. He put up with Garrett Hartley longer than most people would put up with a slacker son-in-law living in the basement. When Hartley was suspended or otherwise indisposed, Payton would resurrect John Carney or John Kasay. When Payton finally had enough of Hartley last year -- a 26-yard miss in the fourth quarter against the Rams finally did it -- he turned to Shayne Graham, the official NFL Kicker of Last Resort who had stints with the Patriots, Giants, Dolphins, Ravens, Texans and Steelers since 2010. Graham missed two field goals in the playoff loss to the Seahawks.

Graham is back, and reportedly had a fine minicamp. A 36-year-old kicker should look pretty good in a practice facility in June, after all. Graham has competition in the form of Derek Dimke, who has been a last-guy-cut type in preseason stints with the Lions and Bucs. Look for Dimke to win the job unless Hartley shows up with a short haircut and a heartfelt apology. Either way, this is a problem until proven otherwise.

Travaris Cadet is the favorite to replace Darren Sproles as the kick and punt returner. Cadet had an 82-yard kickoff return last year, but this is another risky substitution. Brandin Cooks could also handle returns, but he was a master of spinjitsu in college who will have to learn to lay off the highlight stick until he gets his feet wet in the NFL. On the plus side, Thomas Morstead is great on punts and very good (though dome-aided) on kickoffs, and there are no red flags in the coverage units.

29. Detroit Lions

Jeremy Ross returned a punt and kick for a touchdown last year, but both returns came in the Ice Capades game against the Eagles. That does not negate his efforts, but the practice-squad traveler who landed in Detroit after stints in New England, Indy and Green Bay may not be nearly as dangerous when the coefficient of friction increases.

A bigger problem for the Lions is their lack of an experienced kicker to replace David Akers. Rookie Nate Freese was 20-for-20 in his final season at Boston College, and he also kicked off and punted. He is not known for his leg strength, but gets high marks for kicker mechanics from those who understand kicker mechanics. The alternative is Giorgio Tavecchio; if Havard Rugland was "Kickalicious" in Lions camp last year, Tavecchio is "Kickalizioso." One of these guys could be the next Eddie Murray or Jason Hanson and kick for the Lions until my retirement. But for now, they are unproven and risky, and the Lions have no money for an emergency veteran.

30. Buffalo Bills

The Bills have a kick coverage superstar named Marcus Easley, who made 19 solo tackles on kicks and punts last year. But why was Easley forced to impersonate Steve Tasker? Dan Carpenter's low touchback percentage (41 percent, 24th in the NFL) was part of the problem: More returnable kicks mean more tackles for Easley types. Punters Shawn Powell and Brian Moorman were a bigger issue. Powell was released after booting returnable line drives straight at Travis Benjamin in the Browns loss, prompting the return of Moorman, whose leg is nearly gone. Harvard punter Jacob Dombrowski will challenge Moorman in camp.

Leodis McKelvin returned three punts for touchdowns in 2011 and 2012 but averaged just 5.6 yards per return last year. It's misleading to judge returners based on one or two plays (or the lack of those plays), but whether it was McKelvin, his blockers or the circumstances, the Bills return game was lacking. Marquise Goodwin was also ineffective on kickoff returns despite track-star speed. Carpenter was fine on field goals, but the Bills aren't getting the production from teams that they got in the mid-to-late 2000s, when their special teams were often their best attribute.

31. Houston Texans

Shane Lechler did what he did best last year, booming a zillion punts for an awful team, but other Texans specialists did not live up to their end of the bargain. Kicker Randy Bullock was 1-of-5 beyond 50 yards and provided a lot of low line drives on kickoffs. Returner Keshawn Martin provided a punt return touchdown but lots of fair catches (21) and lots of six-yard returns. Opponents averaged 12.3 yards per punt return, so the coverage units weren't great. No one noticed, because the Texans punted less frequently than other bad teams, thanks to all the pick-sixes.

Martin has the chops to be a great returner, so much of this ranking rests on Bullock. The Texans signed Chris Boswell of Rice as a challenger, and Boswell has a great kickoff leg, with 54 touchbacks in 70 attempts last year. But like Bullock, Boswell's field goal accuracy beyond 40 yards or so is questionable. A roster overhaul should help the coverage and blocking units, but kicker is likely to remain a problem spot until Bill O'Brien can get to it.

32. Oakland Raiders

Sebastian Janikowski missed two field goals inside 40 yards and was just 3-of-7 beyond 50 yards. Long kick percentages fluctuate, but when a veteran kicker suddenly starts missing random 32-yarders on clear days, it's a sign of the beginning of the end. Marquette King has a big leg but had two punts blocked last year. The blocks weren't King's fault: Giants and Jets flew untouched up the middle, their lives made easier by the many college-style punt protection formations the Raiders used for some reason.

Taiwan Jones is a great all-around special teamer, so the Raiders decided to make him a kickoff returner. He averaged just 24.0 yards per return last year, with a long of 41 yards, so it should not be hard to find someone better in the role. All sorts of people rotated at the punt return position before the Raiders settled on undrafted rookie Greg Jenkins last year. Jenkins returned six punts for 49 yards.

The Raiders have been hard-pressed to field a competitive starting 22 in recent years, so naturally special teams were back-burnered. Perhaps the influx of veteran free agents will give the Raiders the luxury of finding better punt protectors and return men. And Janikowski may still have a year or two left of reliability. That's the thing about special teams: they are filled with maybes. Some teams just have more maybes than others.

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Next Week: Running backs and running games get ranked. Will we get Shady, enter Beast Mode or play it safe and follow Purple Jesus? Find out after the fireworks.