Sports on Earth's NFL writers Mike Tanier, Dan Pompei, Russ Lande and Robert Weintraub will be providing an offseason assessment of all 32 NFL teams -- identifying the most pressing problems facing each one and proposing the best solutions. Click here for links to every entry in the series.

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The Chargers showed up to the 2013 playoffs uninvited, then made themselves at home by winning a playoff game. It was a remarkable run, but also a mysterious one. Philip Rivers and Antonio Gates played like they just hopped out of a time machine from the Marty Schottenheimer era. The Chargers' lone new star was Keenan Allen, America's premiere Anquan Boldin impersonator. Their defense was anonymous and terrible, and their playoff tiebreaker scenario was the kind of puzzle used as a trick question in an LSAT prep class.

If we cannot make heads or tails of the Chargers 2013 success, how can we build upon it? One thing is certain: The Chargers defense was one of the worst in the NFL, and it needs serious upgrades. As GM for a Day, we will do whatever we can to improve the defense of a team with few on-campus blue chips, little cap space and a late draft slot. The defensive rebuild can keep the Chargers in the wild-card hunt and prepare the Chargers for life after Rivers and Gates, though it is no longer clear exactly when that life will begin.

Problem: The Chargers defense stinks.
Solution (Part 1): Identify the core in-house talent.

The Chargers have already started this process by signing linebacker Donald Butler to a multi-year contract. Butler is just 25 years old, has been a starter for three years and is the best all-purpose defender on the Chargers front seven. He will look a lot better when there is better talent surrounding him.

Corey Liuget had an off year in 2013, but 24-year old, 300-pound three-year starters with pass-rush ability do not grow on trees. Liuget is now in the option-extension stage of his 2011 rookie contract, and the Chargers should be thinking long-term deal. Like Butler, he will look much better with younger, more athletic pass rushers around him and a better secondary behind him.

Eric Weddle is the only player in the secondary worth a hoot, and he has two high-salary years left on a lucrative contract he signed in 2011. Weddle just turned 29, and contract extensions for defenders nearing 30 can be risky, but the Chargers need Weddle's talent/experience/reliability combination. Extending Weddle can also make him more cap-friendly in 2014 and 2015, as some Weddle Bucks can be converted into Liuget Space.

Liuget, Butler and Weddle form the spine of what can potentially be a true playoff-caliber defense (as opposed to a defense that somehow winds up in the playoffs). Add Manti Te'o, who is developing into a capable run defender at inside linebacker; Kendall Reyes, Liuget's young bookend on the 3-4 defensive line; and Melvin Ingram, who finally saw the field at outside linebacker for a few snaps last year after a nasty 2012 injury; and the Chargers have building blocks. That said, there is a lot of building left to do.

Problem: The Chargers defense stinks.
Solution (Part 2): Acquire budget-friendly free agents.

The Chargers don't have the cap maneuverability to be major players in bidding wars for the Jairus Byrd tier of free agents. At the same time, they are so needy for playmakers that they cannot afford to simply ignore the market. The Chargers must rummage through the dented-and-bruised bins for potential bargains who can be cheaply discarded if they do not pan out.

Former Giants cornerback Terrell Thomas appeared destined to be a perennial Pro Bowler before suffering approximately 742 different knee injuries. Finally healthy last season, Thomas played like someone who spent two full seasons running in a swimming pool. Thomas is a smart, high-effort defender, and an extra year of confidence in his knees may help him reclaim some percentage of his 2010 potential. Jabari Greer, a Saints cap casualty, is still effective but old and coming off an injury. Both Thomas and Greer are likely to accept one-year, incentive-laden "prove-it" deals, adding depth, experience and competition to the Chargers secondary at reasonable rates.

Everson Griffen is one of the great enigmas of this free agent class. He has drool-worthy talent, and some team may break the bank on him if its owner goes into "briefcase full of Benjamins and a case of Courvoisier" mode. But Griffen had a troubled early career and has never been consistently productive. A move to outside linebacker in John Pagano's 3-4 is plausible, and it could light a fire in Griffen's boxers. The Chargers should at least feel around to gauge the Griffen market.

A deep free-agent rummage can also produce the likes of Frank Zombo, a former Ted Thompson Packers plug-'n'-play surprise who resurfaced during the Chiefs pass rusher injury rash last year. Zombo turns 27 … on March 5. Happy Birthday Zombo! He can be effective as a situational pass rusher and start in a pinch. Remember that we are building a whole depth chart here: Zombo joins a team with Jarret Johnson and an over-the-hill and out-of-position Dwight Freeney as the starters, an unproven Ingram as the primary sub and a bench populated with nobodies. The Chargers need to create competition up and down the depth chart; players like Zombo, even if they are released in September, can make that happen.

Problem: The Chargers defense stinks.
Solution (Part 3): Draft for all three levels.

Let's grab a pass rusher for the Chargers in the first round. Auburn's Dee Ford may drop into their lap. Ford has electrifying pure speed off the edge, enough technique to win some battles against offensive tackles and a tenacious love of chasing quarterbacks. If Ford is off the board, Louisville's Marcus Smith is a good Pagano system fit. Smith is more technically proficient than Ford, but less explosive. Pagano does not ask his outside linebackers to do anything radical in coverage (which is why we are plucking from the smaller defensive ends), but Smith is more capable to occupy a zone than some of the other pass rushers available in the early rounds. To head in a slightly different direction, Ohio State's Ryan Shazier is a more traditional outside linebacker who can be effective in coverage but still has the initial quickness to upgrade the pass rush.

Next, let's replace free agent Cam Thomas at nose tackle. Penn State's DaQuan Jones, Tennessee's Daniel McCullers and Louisiana Tech's Justin Ellis will all be available on the second day of the draft, and all provide a meaty middle presence. Jones is the most polished, McCullers the most massive. Ellis' quickness and intensity during Senior Bowl practices turned some heads -- 330-pound men are not supposed to move so quickly.

Let's see … a safety to team with and learn from Weddle would be nice. Vinny Sunseri is a coach's kid steeped in Saban science. He's a step slow, a little short and coming off an ACL injury, so he will be available in the late rounds. Rehab is going well, and Sunseri can be a special teams captain who provides quality depth.

We added some veterans at cornerback; now let's bring in a developmental prospect. Duke's Ross Cockrell drove Texas A&M's Mike Evans to distraction in their bowl game. Cockrell is a small mix-it-up type with good instincts, plenty of hustle and enough speed to get by. He could become the next Jabari Greer.

There is always a place for a high-effort pass rushing tweener on the Pagano bench. And Te'o proved that San Diego is a great place for a player to go if he wants to avoid a media feeding frenzy. Michael Sam can provide competition, depth and upside in the late rounds.

A Ford-Sunseri-Cockrell-Sam draft would give the Chargers four guys who flat-out love to play defense; Ford and Jones or Ellis would add high-end tools. The Chargers' playoff success was a mixed blessing, moving the Chargers a half dozen draft slots to 25th, down from their .500-hangaround peers and probably removing them from contention for the Kyle Van Noy/Ra'Shede Hageman class of prospects. But mixed with the useful incumbents and some discount free agents, this is a fine haul.

Problem: An old offense.
Solution: Let nature take its course.

Philip Rivers and Antonio Gates are each under contract through 2015. Rivers had a career renaissance last season, so instead of talking about a cap cut (that is really where he was heading in 2011 and 2012) we must entertain the possibility of an extension.

Rivers is one of the strangest quarterbacks in history: a jalopy of an athlete who somehow never gets injured, a player whose career arc made perfect sense until Mike McCoy and Ken Whisenhunt arrived and jacked him into the Peyton Manning-Kurt Warner matrix. Rivers mixes Bernie Kosar's delivery with Ron Jaworski's durability, Jim McMahon's personality and Lyle Lovett's wardrobe. He's fun, he's fascinating, and you have to be an incurable optimist to want to extend lucrative paydays past his 34th birthday.

Gates is also coming off his best season in four years. But Gates is older, plays a more physically demanding position and showed obvious signs of wearing down last year. The Chargers have an exciting heir apparent on the roster in Ladarius Green, so they should let Gates play out the string. Gates' cap numbers over the next two years are manageable.

Center Nick Hardwick was drafted in the same year as Dan Fouts -- oops, make that Rivers -- and is in the final year of his contract. It has been a fine run. Developmental centers can be found in the late rounds of the draft. Florida State's Bryan Stork is a smart and scrappy type who held his own against some of the better defensive tackles at the Senior Bowl.

While Rivers and the other veterans keep the offense intact, the team must build a new nucleus around Keenan Allen. Green has the tools to be a part of that nucleus. Ryan Mathews can spend another year proving that he has figured things out. As for quarterback … Brad Sorensen is the only prospect on the roster, and the Chargers are not in great position to spend a mid-round pick on an AJ McCarron type. Sorensen should be given lots of first-team reps, and perhaps some preseason starts, while Rivers tees off at The Grand Del Mar. We cannot build a whole new Chargers infrastructure in one day, or even one season. But we can build a defense, and build a stronger foundation atop last year's surprising success.