Given the yearly turnover in college football, it's hard to maintain cohesive star-studded position units for multiple years. Still, sometimes teams get lucky and find surprises to create unstoppable position groups, and sometimes coaches are so good at recruiting and identifying system fits that certain teams boast great groups at certain positions every year. You can probably guess whom for the latter.

Heading into 2014, a few obvious candidates return at each group, where a combination of talent, experience and depth sticks out in making a team clearly superior to most of the rest of the country at a position, whether it's Alabama's collection of big running backs or Clemson's fearsome pass rush. As Sports on Earth's Mike Tanier checks in weekly with evaluations of the NFL's top units, here we'll compile the college version, identifying the best team and conference for each positional unit, as well under-the-radar groups worth watching.

Quarterbacks

Best Team: Florida State. Last year, there was no debate, if we're talking about full units. Not only did Florida State have the signature player of the year in Heisman winner Jameis Winston, but probable 2014 Alabama starter Jacob Coker backed him up. The increasingly important quarterback transfer market diminishes the number of slam-dunk backups, making this ranking almost totally reliant on who the starter is. If all goes well, only the starter will take meaningful snaps anyway. The debate really comes down to two players/teams: Florida State's Winston, or Oregon's Marcus Mariota, who seem to be fighting for college football's quarterback crown, the Heisman and the No. 1 pick in next year's draft, a step ahead of the rest of the field. Given the difficulty Winston faces in trying to win the Heisman again, Mariota is probably the better bet in that department, and overall it's a toss-up. Mariota is the most complete player in college football, the engine behind Oregon's prolific offense as both an accurate and smart passer and a great runner. Winston, however, showed last year that he has unmatched arm strength to go with a knack for Manziel-ian big plays and improvisation, and for now he -- and therefore Florida State -- gets the slight edge. Behind him, with Coker gone the backup job slides to sophomore Sean Maguire, who saw limited garbage-time action and threw for 116 yards with two touchdowns and two interceptions.

2. Oregon
Marcus Mariota, Jeff Lockie

3. UCLA
Brett Hundley, Asiantii Woulard

4. Ohio State
Braxton Miller, Cardale Jones

5. Baylor
Bryce Petty, Seth Russell

6. Auburn
Nick Marshall, Jeremy Johnson

Worth Watching: USC. Even with Max Wittek transferring to diminish the depth, USC has a lot to like at quarterback. Not only does USC have one of the most underrated players in the country at quarterback in Cody Kessler, but it has a backup some assume will beat him for the job. Kessler settled into a nice rhythm post-Lane Kiffin and ended up completing 62.2 percent of his passes for 2,967 yards with 20 touchdowns and seven interceptions. Behind him, redshirt freshman Max Browne hasn't played but still claims the status as the nation's No. 1 quarterback recruit in the class of 2013. Kessler is more of a smaller (6-foot-1) timing-and-rhythm type, while the 6-foot-5 Browne is known for his arm strength from the pocket. Whoever plays will have the advantage of throwing to a deep group of receivers for a team that could easily win the Pac-12 South despite all the attention shifting to city rival UCLA.

Best Conference: Pac-12. Last year, the SEC had a high-scoring year with a big group of talented, experienced quarterbacks returning (Johnny Manziel, AJ McCarron, Zach Mettenberger, Aaron Murray, Connor Shaw, James Franklin). Now, it's sort of back to square one, with a pair of runners leading the pack (Nick Marshall, Dak Prescott). That means the quarterback balance of power shifts to the West Coast, and there's really no debate. Both Mariota and Hundley are Heisman favorites. USC and Arizona State have underappreciated starters in Kessler and Taylor Kelly. Oregon State's Sean Mannion threw for 4,662 yards, although life without receiver Brandin Cooks will be tougher. Stanford returns a one-and-a-half-year starter in Kevin Hogan, who is trying to live up to hype that's been around him since he became the starter. Washington State's Connor Halliday and Cal's Jared Goff are returning starters who will throw for a billion yards in Air Raid offenses. Throw in a solid group of receivers, and the Pac-12 is set to put on an aerial show this fall.

Running Backs

Best Team: Alabama. Georgia has the best all-around running back in the nation in Todd Gurley, along with one of the best backups in Keith Marshall. It's hard to argue with anyone who wants to rank the Bulldogs No. 1. But Alabama gets the edge because of Georgia's durability concerns (Gurley missed three games; Marshall tore his ACL in early October), and the fact that the Crimson Tide have a healthy three-headed monster. After Derrick Henry's monstrous breakout performance in the Sugar Bowl, it's almost as if T.J. Yeldon is flying somewhat under the radar, despite rushing for 2,300 yards and averaging over six yards per carry the last two years. The only concern here is ball security; otherwise, Yeldon has proven himself alongside Eddie Lacy as a freshman and as the lead back as a sophomore, with an NFL-desired combination of size (6-foot-2, 221 pounds) and speed. The scary part is that Henry (6-foot-3, 241 pounds) may have as big of an upside as any of Nick Saban's Alabama running backs, and we haven't even mentioned junior Kenyan Drake, who ran for 694 yards (7.5 yards per carry) and eight touchdowns last year but was overshadowed by Henry's bowl-game star turn. Throw in fullback Jalston Fowler, and nobody can match the depth of Alabama.

2. Georgia
Todd Gurley, Keith Marshall, Sony Michel, Nick Chubb

3. Wisconsin
Melvin Gordon, Corey Clement, Taiwan Deal

4. Nebraska
Ameer Abdullah, Imani Cross, Terrell Newby

5. Oregon
Byron Marshall, Thomas Tyner, Royce Freeman

6. Auburn
Cameron Artis-Payne, Corey Grant, Peyton Barber

Worth Watching: Notre Dame. The Fighting Irish never really clicked consistently on offense last year, and part of the reason was a lack of clarity at running back. With mobile quarterback Everett Golson suspended for the season, Notre Dame ranked 81st in rushing, averaging 4.5 yards per carry and 150.9 yards per game. Now, even with George Atkinson gone, there's reason for hope that they'll see a big turnaround. For one, Golson's return gives Brian Kelly more flexibility with his offense, and a mobile quarterback can open up lanes for running backs. Two, the Irish have collected a decent amount of young talent, headlined by redshirt freshman Greg Bryant and sophomore Tarean Folston. In a rotational role, Folston rushed 88 times for 470 yards and three touchdowns as a freshman. Bryant, meanwhile, played sparingly early in the season for a knee injury caused him to take a medical redshirt. The composite rankings on 247Sports rated Bryant sixth and Folston 14th among running backs in the class of 2013, and Notre Dame will be counting on a breakout campaign from at least one of them. And then there's also the fact that Notre Dame actually returns its leading rusher: senior Cam McDaniel, who had 705 yards on 152 carries. Whoever emerges -- and it's a good bet either Bryant or Folston will -- will be part of an offense that should take a big leap forward this fall.

Best Conference: SEC. The Big Ten comes awfully close, with 13 of its top 15 rushers returning, but nobody can touch the SEC, both in terms of talent at the top and all-around depth. Alabama and Georgia might take the crown by themselves, while Auburn returns a trio of talented backs even with Tre Mason gone, South Carolina has one of the nation's best in Mike Davis, and schools like Arkansas (Jonathan Williams, Alex Collins), Texas A&M (Tra Carson, Trey Williams, Brandon Williams), Florida (Kelvin Taylor, Mack Brown, Matt Jones) and Missouri (Russell Hansbrough, Marcus Murphy) all boast experienced committees with multiple capable backs. That's not to mention a pair of potential impact freshman, in LSU's all-world recruit Leonard Fournette, and Tennessee's Jalen Hurd, who participated in spring ball and will compete with senior Marlin Lane.

Receivers

Best Team: Baylor. What Art Briles is doing at Baylor is amazing, and they're an obvious first in ranking receiving corps even after sophomore Robbie Rhodes -- a four-star recruit expected to move into a bigger role -- was dismissed from the team. Top skill-position players want to play for Briles, and for good reason: Oregon is the only school that can rival Baylor's flashy, high-powered offense. Briles likes to spread the field and use as much space as possible while running a rather balanced offense. The running backs remain strong (Shock Linwood, Devin Chafin) despite the losses of Lache Seastrunk and Glasco Martin, but it's the receiving corps that really stands out. There is some concern, as we got a glimpse of the passing game without Tevin Reese when he was hurt late in the season, and it clearly impacted production. Still, senior Antwan Goodley (71 catches for 1,339 yards) returns as one of the nation's best, joined by reliable inside receiver Levi Norwood and a handful of young players ready to emerge: sophomore Corey Coleman (35 catches for 527 yards), junior Jay Lee, redshirt freshman Quan Jones and blue-chip true freshman Davion Hall (in for spring) and K.D. Cannon. Replacing Reese is a tall order, but Bryce Petty will have no problem finding capable options out wide in what should be another season that pushes many offensive records for the Bears.

2. Alabama
Amari Cooper, Christion Jones, DeAndrew White, O.J. Howard, Chris Black, Robert Foster

3. Louisville
DeVante Parker, Eli Rogers, James Quick, Gerald Christian, Kai De La Cruz, Michaelee Harris

4. Stanford
Ty Montgomery, Devon Cajuste, Michael Rector, Jordan Pratt, Austin Hooper, 

5. Arizona
Austin Hill, Nate Phillips, Samajie Grant, Cayleb Jones, DaVonte' Neal

6. Maryland
Stefon Diggs, Deon Long, Levern Jacobs, Nigel King, Amba Etta-Tawo

Worth Watching: South Carolina. It still feels weird saying this about a Steve Spurrier offense, but the Gamecocks will revolve around their running game, with a star tailback in Mike Davis and one of the nation's best offensive lines. Still, in replacing Connor Shaw, senior Dylan Thompson (who is more of a prototypical passer) has an array of options in the receiving corps, even with leading receiver Bruce Ellington gone. Undersized Damiere Byrd has already established himself as a gamebreaker, averaging 17.4 yards per catch last year. Junior Shaq Roland was suspended three games last year, but when on the field he's shown a lot of potential as a deep threat too, averaging 18.2 yards per catch. He had his best game in the bowl, finishing with six catches for 112 yards against Wisconsin. And then there's promising sophomore Pharoh Cooper, a multidimensional threat who played sparingly as a freshman, actually rushing for 202 yards on 20 carries. Entering 2014, Cooper is expected to take on an expanded role out of the slot, on special teams and as a wildcat quarterback, giving the Gamecocks an impressive collection of speed to complement the power of the running game.

Best Conference: ACC. The depth here is really strong, even after the losses of Clemson's Sammy Watkins and Martavis Bryant and Florida State's Kelvin Benjamin and Kenny Shaw, among others. The Seminoles will be more than fine, as they return leading receiver Rashad Greene and one of the nation's best tight ends in Nick O'Leary. Duke's Jamison Crowder, Pittsburgh's Tyler Boyd and Louisville's DeVante Parker are already established stars. Miami's Stacy Coley and North Carolina's Quinshad Davis are rising stars. And even with Eric Ebron gone, the league's roster of tight ends is impressive, with O'Leary joined by Duke's Braxton Deaver, Louisville's Gerald Christian, Miami's Clive Walford and Clemson's Jordan Leggett. The Pac-12 has a strong argument as well, especially with Arizona's Austin Hill returning from a torn ACL, but the ACC gets the slight edge.

Offensive Line

Best Team: Florida State. OK, so the Seminoles lost All-America center Bryan Stork, who is undoubtedly a key loss. But they also return four starters, and you could plausibly put all four returning starters on the preseason All-ACC first team. Left tackle Cameron Erving and right guard Tre' Jackson are already touted as potential first-round picks in next year's draft. Left guard Josue Matias might not be far behind and could even surpass them. Right tackle Bobby Hart has been a steady presence throughout his career. Stork's replacement will likely be senior Austin Barron, who has decent playing experience with five career starts. So there you go: five senior starters, three of whom are All-America candidates, blocking for a Heisman-winning quarterback and a running back who averaged eight yards per carry. It's worth noting that Florida State ranked 87th in sack percentage, but that's the sort of thing that happens when you have a freshman quarterback who likes to hold onto the ball and improvise. The 2015 season will be a big test for Jimbo Fisher's ability to reload, given the loss of an entire offensive line (not to mention the possible loss of Winston, among others), but for now the Seminoles are almost unfairly rich with talent, with a veteran offensive line providing a stabilizing force for the rest of the talented pieces to work around in comfort.

2. Auburn
Shon Coleman, Alex Kozan, Reese Dismukes, Chad Slade, Avery Young

3. Oregon
Tyler Johnstone, Hamani Stevens, Hroniss Grasu, Cameron Hunt, Jake Fisher

4. South Carolina
Corey Robinson, A.J. Cann, Cody Waldrop, Mike Matulis, Brandon Shell

5. Texas A&M
Cedric Ogbuehi, Jarvis Harrison, Mike Matthews, Joseph Cheek, Germain Ifedi

6. Oklahoma
Tyrus Thompson, Dionte Savage, Ty Darlington, Nila Kasitati, Daryl Williams

Worth Watching: Arkansas. Most of the attention around Arkansas has been negative lately, from last year's 3-9 record to Bret Bielema's self-serving anti-tempo campaign. Prospects for getting out of the SEC West basement aren't very good, but don't doubt Bielema's ability to cobble together a strong offensive line. That's what his Wisconsin teams were known for, and while the Razorbacks had a disastrous 2013 season, it doesn't mean the line didn't play well. They ranked sixth nationally in sack percentage, giving up only eight all season, and a stellar running game averaged 5.3 yards per carry behind Alex Collins and Jonathan Williams, who rushed for nearly 2,000 combined yards and both return. The line loses two starters, including All-America center Travis Swanson, who will be impossible to replace, but this is a promising unit with a pair of sophomores, Dan Skipper and Denver Kirkland, who started as true freshman, as well as a solid anchor in senior right tackle Brey Cook. 

Best Conference: SEC. While last year was all about the passing game in the SEC, this year reverts to a more traditional approach: Big linemen paving the way for a deep crop of running backs. While Auburn (Greg Robinson) and Texas A&M (Jake Matthews) lose top draft picks and Alabama still hasn't totally come together, there are plenty of reasons for SEC coaches to be satisfied with their line play. Not only are there already several established standouts (Texas A&M's Cedric Ogbuehi, LSU's La'el Collins, Auburn's Reese Dismukes, South Carolina's A.J. Cann), but a new generation is on the verge of breaking through as well (Ole Miss' Laremy Tunsil, Alabama's Cam Robinson, Texas A&M's Germain Ifedi). The SEC has been dominant at the line of scrimmage for years, and that's not changing.

beasley_clemson
All-America end Vic Beasley headlines a Clemson line that will keep the Tigers near the top of the ACC. (USA TODAY Sports)

Defensive Line

Best Team: Clemson. Once a national college football punch line, the Clemson defense as a whole has reinvented itself as arguably the ACC's best, and even one of the best nationally. The unit has undergone an impressive transformation under former Oklahoma defensive coordinator Brent Venables -- one part of the Tigers' highly paid assistant staff -- and last year saw a breakout for the defensive front, and end Vic Beasley in particular. Beasley finished third in the nation with 13 sacks -- including two each against South Carolina and Georgia -- and fourth in tackles for loss with 23, and he gave Clemson a gift when he decided to return for his senior season. Led by Beasley, the Tigers ranked fourth nationally in sack percentage and first in tackles for loss, with a deep front complementing Beasley. The entire line returns, including standout tackle Grady Jarrett, DeShawn Williams and 335-pounder D.J. Reader in the middle, as well as a group of impressive ends that also includes senior Corey Crawford and emerging sophomore Shaq Lawson. We're accustomed now to Clemson relying on a high-powered offense, but this year the team's identify shifts.

2. Ohio State
Noah Spence, Adolphus Washington, Michael Bennett, Joey Bosa, Tommy Schutt

3. TCU
Devonte Fields, Chucky Hunter, Davion Pierson, Terrell Lathan, James McFarland

4. Florida
Dante Fowler, Darious Cummings, Leon Orr, Jonathan Bullard

5. Texas
Cedric Reed Malcom Brown, Desmond Jackson, Shiro Davis

6. Michigan State
Shilique Calhoun, Joel Heath, Damon Knox, Marcus Rush

Worth Watching: Missouri. Two things can easily diminish the reputation of Missouri's defensive line entering 2014: the losses of acclaimed ends Michael Sam and Kony Ealy, and the SEC title game debacle in which Auburn rushed for 545 yards. Don't let that cloud your view of where the Tigers' front four stands now. Even with that brutal game against Auburn, Missouri ranked a respectable fifth in the SEC in yards per carry allowed (4.17), and an SEC-leading 41 sacks didn't revolve solely around Sam and Ealy. New starting ends Markus Golden (6.5 sacks) and Shane Ray (4.5 sacks) are both proven role players ready to step into starring roles. And the Tigers also return the inside of the line, as Matt Hoch, Lucas Vincent and Harold Brantley all have starting experience at tackle. This will continue to be one of the SEC's best.

Best Conference: Big Ten. Yeah, maybe this should go to the SEC, or maybe the Big 12, but the Big Ten has a talented group of headliners. If Clemson has the nation's No. 1 d-line, then Ohio State is probably No. 1a. The Buckeyes need to be a bit more consistent, but matching the talent of Spence-Washington-Bennett-Bosa is nearly impossible. Elsewhere, Nebraska end Randy Gregory broke out as a juco transfer last year and is hovering near the top of 2015 draft boards, as is Michigan State end Shilique Calhoun, who's coming off an All-America season. Throw in Iowa's Carl Davis, Michigan's Frank Clark, Purdue's Ryan Russell and Penn State's Deion Barnes and C.J. Olaniyan, and there's a lot to like up front for Big Ten defenses.

Linebackers

Best Team: Georgia. The Georgia defense was sort of a mess last year, especially vulnerable to making mistakes on the back end, but the linebacking corps was far from at fault. While the pass rush took a step back after the loss of All-America Jarvis Jones, the Bulldogs had a rising unit that should establish itself as a dominant one in 2014. Inside linebacker Ramik Wilson led the SEC in tackles with 133, and his senior partner in the middle, Amarlo Herrera, was not far behind with 112. Off the edge, Jordan Jenkins had a solid year as the replacement for Jones, finishing with five sacks and 12 tackles. Most notably, sophomore outside linebacker appears destined for stardom. While a bit uneven as a freshman, as expected, Leonard Floyd had 6.5 sacks and nine tackles for loss. Georgia has major concerns about the secondary, but they'll be eased a bit by the pressure the front seven will get on opposing quarterbacks.

2. Oklahoma
Eric Striker, Dominique Alexander, Frank Shannon, Geneo Grissom

3. Alabama
Xzavier Dickson, Trey DePriest, Reuben Foster, Denzel Devall, Reggie Ragland

4. UCLA
Myles Jack, Isaako Savaiinaea, Eric Kendricks, Kenny Orjioke

5. USC
Hayes Pullard, Anthony Sarao, Jabari Ruffin, J.R. Tavai, Lamar Dawson

6. Ole Miss
Serderius Bryant, Denzel Nkemdiche, Tony Conner, Christian Russell, D.T. Shackleford

Worth Watching: Penn State. Linebacker U lacks its usual depth -- something that took another hit recently when junior Ben Kline tore his Achilles -- but that doesn't mean the unit can't be special if it avoids further injuries. Middle linebacker Mike Hull has been a steady presence, while sophomore outside linebackers Brandon Bell and Nyeem Wartman have both flashed signs of stardom and could be on the verge of breakouts. All bets are off if there's another injury, which is something we can say about most of Penn State's units amidst NCAA sanctions, but there's a lot to like about the defense's starting 11, especially if Bell and Wartman come through.

Best Conference: SEC. The Big Ten lost a deep pool of impressive linebackers, while the SEC gets everyone but Alabama's C.J. Mosley and LSU's Lamin Barrow back, for the most part. As stated, nobody can match Georgia's group in its 3-4 alignment, and while Alabama experiences some turnover, it has a veteran Trey DePriest surrounded by a bunch of rising talents. Ole Miss boasts a deep group too, and players like Tennessee's A.J. Johnson, Mississippi State's Benardrick McKinney, LSU's Kwon Alexander and Florida's Antonio Morrison fill out a stellar arsenal of linebacking talent.

Defensive Backs

Best Team: Virginia Tech. What's most amazing about Virginia Tech's strength is the secondary is the players who are not in Blacksburg anymore. All-ACC cornerbacks Kyle Fuller and Antone Exum were both drafted, but the sophomores taking over as full-time starters have the chance to be as good or better. Fuller's brother, Kendall Fuller, ended up starting 12 games last year (both Kyle Fuller and Exum dealt with injuries) and earned second-team All-ACC honors, recording six interceptions and 58 tackles. Facyson also got plenty of national attention and intercepted five passes in nine starts. That the Hokies could lose two impact corners and still end up with arguably the best duo in the country, as only sophomores, is remarkable, and sets up coordinator Bud Foster well for yet another successful season on defense. Of course, it doesn't stop there: The Hokies return two senior safeties, Detrick Bonner and Kyshoen Jarrett. Both had two picks last year, while Jarrett is the team's leading returning tackler (71). Opponents averaged only 6.2 yards per attempt with 12 touchdowns and 19 interceptions against Virginia Tech last year, and the Hokies ranked fifth in pass efficiency defense. While a disruptive pass rush helped pave the way for such a great season, there shouldn't be much of a drop off, if any, especially with the Fuller-Facyson tandem now having a full season under their belts.

2. Florida State
P.J. Williams, Jalen Ramsey, Tyler Hunter, Nate Andrews, Ronald Darby

3. USC
Josh Shaw, Su'a Cravens, Leon McQuay, Kevon Seymour

4. Michigan State
Trae Waynes, Kurtis Drummond, Darian Hicks, R.J. Williamson

5. Florida
Vernon Hargreaves, Jabari Gorman, Keanu Neal, Jalen Tabor, Brian Poole, Marcus Maye

6. Texas
Quandre Diggs, Mykkele Thompson, Josh Turner, Duke Thomas

Worth Watching: UCF. Losing quarterback Blake Bortles and running back Storm Johnson early to the NFL is huge, but it isn't the end of the world as the Knights pursue back-to-back major bowl appearances. A solid defense should be the American Athletic's best this season, led by an experienced secondary that returns all four starters. Last year, UCF allowed opposing quarterbacks to complete 56.8 percent of their passes for an average of only 6.5 yards per attempt, even with a mediocre pass rush up front. Three of those four returning starters are seniors, but the real star will be sophomore Jacoby Glenn, who earned first-team all-conference honors as a freshman. They'll get an early test against Penn State's Christian Hackenberg in the opener in Ireland.

Best Conference: ACC. The ACC can take the crown just by combining Virginia Tech and Florida State, which are both head and shoulders above the rest of the nation in terms of starting secondary talent. Even with the loss of defensive leader Lamarcus Joyner, the Seminoles are ready to reload for a unit that ranked No. 2 in pass efficiency defense on a team that led the nation in interceptions. Beyond the two star-studded lineups, cellar-dweller Virginia boasts a solid, experienced unit led by safety Anthony Harris, and Clemson is expecting big things out of redshirt freshman cornerback Mackensie Alexander.

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Contact me at matt.brown@sportsonearth.com and follow me on Twitter @MattBrownSoE.