The Chargers defense suffered a major blow Tuesday on the practice field.

Outside linebacker Melvin Ingram tore his ACL on the second day of organized team activities. The left knee injury likely spells the end of his season, and the 2012 first-round pick is scheduled to receive further evaluation before undergoing surgery.

San Diego was leaning heavily on Ingram for its outside pass rush in 2013. It lost Shaun Phillips and Antwan Barnes in free agency.

On Monday, coach Mike McCoy spoke highly of Ingram.

"We talk about it all the time as a staff: the best coverage is a good pass rush," McCoy said. "When you have someone like that coming off the edge, his ability to get to the passer, that's key for our system and our success. There are some very good quarterbacks we play against, and we have to get pressure on them."

A No. 18 overall pick, Ingram had one sack as a rookie.

But the frequency at which he came to a handful of others — he netted a team-high 29 quarterback hurries — had the Chargers brass expecting a significant spike from the 24-year-old in his second season.