Melvin Ingram has sustained a knee ligament tear during a practice session with the San Diego Chargers.
The team's doctors confirmed that the linebacker tore the anterior cruciate ligament in his left knee yesterday.
The 24-year-old is likely to miss the entire 2013 NFL season if he needs surgery to repair the damage.
Ingram made 41 tackles during his rookie season with the Chargers, including one sack and one forced fumble.