Roster analysis: Time for Corey Liuget to shine on Chargers' defensive line

SAN DIEGO -- Although he led the San Diego Chargers in sacks the past two seasons, some NFL observers were surprised the team signed defensive lineman Corey Liuget to a five-year, $58 million deal that includes more than $30 million in guaranteed money. The contract makes Liuget one of the highest paid 3-4 defensive ends in the league. Now, the 25-year-old has to play up to his potential, justifying San Diego signing him to the lucrative deal.

Lock: Liuget, Kendall Reyes, Ricardo Mathews

Looking good: Sean Lissemore, Ryan Carrethers, Mitch Unrein, Tenny Palepoi

On the bubble: Darius Philon, Damion Square, Cameron Botticelli.

The good: The Chargers bring back experienced depth up front, with all three starters returning in Liuget, Reyes and Lissemore. Mathews will pair with Liuget to get after the quarterback on passing downs. Carrethers, Unrein and Palepoi are capable backups. Liuget led San Diego in sacks (4.5) and tackles for loss (19) last season. He also scored his first career touchdown by recovering a fumble in the end zone against the San Francisco 49ers in Week 16 last season.

The bad: The Chargers finished with just 26 sacks last season, No. 29 in the NFL. And they gave up an average of 4.53 yards per carry in 2014, also 29th in the league. Defensively, the Chargers must be stout against the run, and have to generate more pass rush from the interior of the defense. The Chargers have not had a true, two-gap nose tackle that controls the middle of the defense since Jamaal Williams' final year with the team in 2009. But defensive coordinator John Pagano relies more on movement in his 3-4 defense. Lissemore and Carrethers will compete for time at nose tackle, and the Chargers must get more production from the inside linebacker position.

Bottom line: The Chargers gave up an average of 4.22 yards per carry on first-down rushes last season, which was No. 22 in the NFL. If San Diego wants to be considered an elite defense, the Chargers have to be better stopping the run on first down. And that starts up front. "I’m impressed by our work ethic, and I think the competition at each position will bring out the best," Chargers defensive line coach Don Johnson told the team’s web site. "This group is still young. You have guys right at the pinnacle of their career where it’s make or break, and I think that is exciting."