SAN DIEGO -- The Chargers earned a playoff spot for the fourth time in five seasons and won a playoff game for the second consecutive year. The Chargers' late-season push past Denver in the AFC West and into the AFC divisional round put a positive spin on an otherwise disappointing season that exposed several glaring weaknesses, especially on defense and the offensive line.

While the Chargers provided plenty of entertainment during a wacky season that somehow ended in the playoffs, they ultimately finished with an underwhelming 9-9 record. The team's playoff charge didn't alter the offseason checklist of A.J. Smith, who's facing what will be the busiest offseason in his tenure as Chargers general manager.

"It doesn't change my feeling at all," Smith said last week. "… We've got some good players, but we've got to find a mix that can make some noise in the playoffs and continue to build a resume of success in pressure-packed situations."

There are several problem areas that must be fixed if the Chargers are to remain among the NFL's elite, and Smith will address them through the NFL draft, free agency or from within. He won't discuss those plans until the last week of February, but that shouldn't stop us from speculating.

In this writer's opinion, these are the top five trouble spots and how the team should/might fix them:

Running back

What went wrong: LaDainian Tomlinson spent the regular season battling a toe injury, only to have his hamstring act up at the wrong time and keep him out of the postseason for the second straight year. His effectiveness was hindered by injury and a disappointing season by the offensive line, leading many to wonder if Tomlinson's best seasons are behind him. Darren Sproles proved to be an explosive, entertaining, change-of-pace back capable of breaking a big play at any time. While the 5-foot-6, 181-pound slasher can run between the tackles, his status as an every-down back remains in question and makes him an unlikely heir to Tomlinson's spot. He is an unrestricted free agent, and some team might pay top dollar for his ability as a returner, rusher and receiver.

If we were king: We'd keep both players, but only at the right price. If Tomlinson is willing to renegotiate his contract to ease the team's salary cap hit ($8.8 million in 2009) in the interest of having better players around him and a better shot at a Super Bowl ring, we'd go for it. If he's not, we'd keep him anyway and address the situation again after 2009. While he has had his injury problems and history suggests diminishing returns in future seasons, Tomlinson is still one of the best running backs in football when he's healthy and the offensive line is productive. Fans can be a bit too reactionary at times, focusing on Tomlinson being sidelined during playoff losses to Pittsburgh and New England over the last two seasons as opposed to the fact that he won the NFL rushing title in 2006 and 2007 and finished 10th in 2008 despite a career low in carries. The chief question is this: Is there a better alternative for a team with Super Bowl aspirations, especially considering that cutting Tomlinson comes with $2 million cap hit? There's no point in making moves for the sake of change. If Sproles would accept a continuation of his current role plus 10 more carries per game, he'd be worth more than the average backup. If some team offers him much more, we'd wish Sproles luck and find Tomlinson's heir in the draft.

What Smith might do: He's not the sentimental type. Tomlinson's past production and status as fan favorite will have little bearing on his future with the team. Smith likely will ask Tomlinson to take a pay cut, and might go in a different direction should negotiations go south. He'll offer Sproles a deal that's reasonable for a player with 20 all-purpose touches per game, but nothing more. If both end up elsewhere, Smith might draft a rusher early (Ohio State's Chris "Beanie" Wells at No. 16?) in hopes of replacing ground production.

Offensive line's right side

What went wrong: The Chargers stuck with right guard Mike Goff a year too long and turned to tackle Jeromey Clary full time a year too soon. Clary is talented, but he got beaten too often against quality competition. That forced the Chargers to become predictable and run left behind Pro Bowler guard Kris Dielman and tackle Marcus McNeill.

If we were king: We'd let Goff walk as an unrestricted free agent and monitor Clary's development throughout the offseason, but bring in some competition at tackle to keep him motivated. As for the opening at right guard, that should be an option for early in the draft and in free agency to ensure depth at a pivotal position.

What Smith might do: Fixing the offensive line will be a top priority, because strength and depth up front can make an average back look like an All-Pro. Smith, who has found diamonds in the rough at this position before, will try to do so again to solidify this sore spot and make the Chargers' offense even better than it already is.

Safety

What went wrong: Clinton Hart lost his hold on the starting spot at strong safety late in the season. Although he was playing with shoulder and neck injuries, Hart had some trouble in deep coverage. Eric Weddle was inconsistent in his first season as a starter, faltering at certain times while flashing some real potential at others.

If we were king: We'd give Weddle time to develop and leave him in the starting lineup. He has too much upside to do anything else. While Steve Gregory performed well at times and earned playing time over Hart as the year progressed, he's not ready to become a starter. Hart could return to form next season, but we'd spend some free-agent dollars to increase competition and bring in an intimidator who isn't afraid to make the big hit.

What Smith might do: This seems like a logical spot for a free agent to fill in at strong safety and shore up a pass defense that struggled mightily. If Smith finds a college safety with big upside, he might fill this need through the draft, relying on Hart and Gregory until that player is ready.

Defensive line

What went wrong: With Jamal Williams? Absolutely nothing. The Chargers' nose tackle rarely played better than he did down the stretch, stuffing the run frequently. The Chargers struggled at both end positions, however. Igor Olshansky's role became insignificant in the defensive scheme, while Luis Castillo was more inconsistent than in seasons past.

If we were king: Castillo is a legitimate talent, and should rebound in a big way. Olshansky, an unrestricted free agent, would be allowed to leave and his replacement could come from within. Ryon Bingham has shown potential, but another end would be added to increase numbers and fill out the depth chart. The draft would be the preferred method of finding an end, although the Chargers must think about selecting Williams' heir apparent in the near future.

What Smith might do: Smith has picked defensive linemen early in the draft a few times, but with the Chargers' other needs, that might not be in the works this year. He might trade a few picks for an established pass rusher, depending on the compensatory draft picks the Chargers receive.

Outside linebacker

What went wrong: Shawne Merriman played in only one game because of a bum knee, which hurt the Chargers' pass rush and the defense as a whole. Merriman compensates for ills in pass coverage and makes other players better by commanding so much attention. Without him, the Chargers' pressure on opposing quarterbacks went from excellent to average.

If we were king: Getting Merriman back is like signing an A-list free agent without the salary cap hit. His contract runs out in 2009, and after what happened to the Chargers' pass rush in 2008, signing him to a long-term deal should be a priority eclipsed only by a contract extension for quarterback Philip Rivers. He'll also make Shaun Phillips a more productive player, after the standout from Purdue recorded 7 1/2 sacks despite dealing with extra blockers.

What Smith might do: Add depth and injury insurance to the position. Antwan Applewhite showed promise, and Jyles Tucker can still get after the quarterback, but adding pass rushers never hurts. If Smith can find some talent that fits the Chargers' system, he'll take them in the later rounds or as undrafted free agents.

What would you do to fix the Chargers and how would you address this offseason? Send your solution to sports@nctimes.com, and we might publish your response later this week. Contact staff writer Scott Bair at (760) 739-6642 or sbair@nctimes.com