SAN DIEGO -- Chargerscoach Mike McCoy confirmed that wide receiver Keenan Allenhas suffered an ACL tear in his right knee and is done for the year after the team received results from an MRI on Monday.
The Chargers will place Allen on injured reserve and use his vacant roster spot to activate rookie defensive end Joey Bosa from the exempt list.
According to ESPN's Adam Schefter, Allen also suffered some minor cartilage damage in addition to the ACL tear.
Allen also finished last season on the injured reserve list after suffering a lacerated kidney in a Week 8 contest against the Baltimore Ravens.
Allen, 24, suffered the knee injury with just over two minutes left in the second quarter of the Chargers' 33-27 overtime loss. His right knee appeared to buckle as he came out of a break, and he fell to the ground. Teammates gave Allen a hug as he was carted off.
The Chargers will look to receivers already on the roster like Travis Benjamin, Dontrelle Inman and Tyrell Williams to help replace the production lost by Allen's absence.
San Diego also could bring in an experienced veteran like James Jones into the fold. Jones was with the Chargers during training camp, but he was cut in San Diego's effort to get down to 75 players.
Bosa is hopeful to practice in pads this week for the first time since signing his rookie contract two weeks ago, after remaining unsigned for over a month due to a contract stalemate over offset language and the earlier payment of deferred signing bonus money.
Bosa practiced just once the day after he signed his deal in a helmet, jersey and shorts before suffering a minor hamstring injury.
McCoy reiterated that he will not provide a time table for Bosa's first game with the rest of his teammates.
"Joey is day-to-day," McCoy said. "I can't tell you if it's going to be Wednesday or Thursday -- I don't know that right now.
"He's working with trainers today [Monday], and he'll be working with them tomorrow. He's got to do certain things to get on the field. And we've also got to be smart with it so we've got him for the long haul.
"We got to make sure we do it the right way, so when he's out there he can help our team and play 60 minutes of football."