SAN DIEGO -- Chargers outside linebacker Dwight Freeney has a torn quadriceps muscle that could sideline him for several weeks or even the rest of the season.

A source had earlier told ESPN NFL Insider Adam Schefter that Freeney's quadriceps tendon was torn, but another source later confirmed a comment by general manager Tom Telesco that the injury was to Freeney's quadriceps muscle.

Coach Mike McCoy and Telesco both said Monday that the team doesn't know the severity of the injury or the time frame for recovery for the 33-year-old pass rusher.

Freeney was hurt in the second quarter of San Diego's 30-21 victory against Dallas on Sunday. After being tended to for several minutes, he walked off the field without help.

McCoy said the team and Freeney are exploring their options. Freeney could be placed on injured reserve designated, which would allow him to return later in the season.

"He's talking to some people, we're talking to people and just really kind of figuring out what is the best way to go," McCoy said. "That is a possibility. We'll just wait and see in the next couple of days, the severity of it exactly, what our plan is going forward."

If Freeney was placed on injured reserve designated, he'd be eligible to return to practice in six weeks. He'd be eligible to return to the active list after eight weeks.

If the injury is more significant, he could be lost for the season.

After starring for Indianapolis for 11 seasons, Freeney was released in the offseason after his production dropped for the third straight season.

He sat on the free-agent market for more than two months before the Chargers signed him in late May, days after Melvin Ingram tore up his left knee in an offseason workout.

Freeney was Indianapolis' career sacks leader with 107½. He had one half-sack with the Chargers and provided a strong presence off the edge.

"Anytime you lose a great player like Dwight Freeney, it's a blow to your team," McCoy said. "That's offense, defense, special teams, in your league. When you lose one of the greatest players of all time on your team, with an injury like that, in a game, that's tough. I give a lot of guys credit for stepping up."

ESPN NFL Insider Adam Schefter and The Associated Press contributed to this report.