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 Melvin Ingram

Age: 24

The skinny: Selected No. 18 overall in the 2012 draft by the Chargers, Ingram made a miraculous comeback from surgery to repair a torn anterior cruciate ligament in his left knee last May. After a six-and-half month rehabilitation, Ingram returned to play in four regular season contests and the postseason last year. And although he totaled just eight tackles, a sack and a forced fumble during the regular season, Ingram’s impact can’t be measured by statistics alone. The South Carolina product brought an added boost to practice sessions, along with an infectious energy and enthusiasm that rubbed off on the rest of the defense during games.

Reason for optimism: With another offseason of rehabilitation, rest and recovery, Ingram will be closer to 100 percent healthy for the upcoming season. And the return of a healthy Dwight Freeney should make things easier for Ingram in terms of getting after the passer. Ingram and Freeney will pair to create one of the better pass-rush duos in the NFL in 2014.

Reason for concern: Complacency. ESPN NFL Insider Matt Williamson praised Ingram’s explosiveness and versatility. But like fellow teammate Eric Weddle says, Ingram can’t believe the hype. He still has just two sacks in 20 NFL games, so there’s ample room for improvement. Ingram has to turn his enormous potential into consistent performance at a high level. And having two healthy knees will go a long way in helping Ingram accomplish that feat.