Bolts All Under-25 team: Thomas Keiser

In this series we take a look at 12 players for the San Diego Chargers who are 25 or younger and who could be considered foundational or impact players.

Player: OLB Thomas Keiser

Age: 25

The skinny: Signed as an undrafted rookie free agent out of Stanford by the Carolina in 2011, Keiser joined the Chargers in free agency in May 2013 after being waived by the Panthers. Keiser spent the first four weeks of the regular season on the practice squad. But due to an season-ending injury suffered by outside linebacker Dwighty Freeney, Keiser was signed to the active roster after Week 4, emerging as San Diego’s most effective edge rusher. Keiser finished the season with a career-high 4.5 sacks, and also corralled a game-clinching interception in San Diego’s most impressive win last season at Denver.

Reason for optimism: At 6-4 and 260 pounds, Keiser has the size and athleticism the Chargers are looking for from an edge rusher. Keiser played a career-high 380 snaps last season. Pass rushers tend to get better with age, learning better technique and more subtle moves to get after the quarterback. With more playing time, Keiser should emerge as a more accomplished pass rusher.

Reason for concern: Like he has throughout his four-year NFL career, Keiser will be fighting for a roster spot. Outside linebacker is one of San Diego’s deepest positions on defense. Freeney and Larry English return from season-ending injuries. Melvin Ingram is a year removed from major knee surgery, and Jarret Johnson and Reggie Walker are veterans who can rush his passer and know San Diego’s scheme defensively. So Keiser will have his work cut out for him to carve out a niche on the Chargers’ defense.