NFL sacks king Elvis Dumervil might miss the season with a torn chest muscle.
A person familiar with the injury to Dumervil told The Associated Press the Denver Broncos pass rusher has torn his pectoral muscle and could be sidelined up to five months.
The person spoke on the condition of anonymity on Thursday because the Broncos have not yet made an announcement.
A Broncos spokesman said coach Josh McDaniels was expected to address the issue following Thursday afternoon's workout.
ESPN first reported the extent of the injury Thursday. Dumervil was hurt at practice Wednesday night, walking off the field clutching his right arm following a defensive drill.
Dumervil led the league with 17 sacks in 2009 and parlayed his breakout season into a five-year, $58.332 million extension last month that included $43.168 million in guarantees, a record for a pass rusher.
Without Dumervil, the Broncos lack a bona fide pass rusher. Defensive lineman Darrell Reid had four sacks last year, the most of any other returning Broncos player.
But Reid is currently sidelined with a knee ailment and hasn't participated in training camp.
The other outside linebackers this season, former first-round picks Robert Ayers and Jarvis Moss, didn't have a sack last year.
The Broncos were hoping that new nosetackle Jamal Williams would practice for the first time at camp Thursday. McDaniels hasn't said whether Williams has been held out for injury or conditioning reasons. The 348-pound Williams was brought in to help push the pocket and allow Dumervil to get to the quarterback more often.
Now, that plan has to be altered.
Training camp has gotten off to a bad start for the Broncos. They lost their top two tailbacks, Correll Buckhalter (back) and Knowshon Moreno (hamstring), on the first day of camp.
Inside linebacker D.J. Williams, one of the leaders of the defense, has missed practices for unspecified reasons.
Just when the Broncos received backfield reinforcements by signing LenDale White on Wednesday, their All-Pro linebacker got hurt.
Dumervil prospered last season in the Broncos' new defensive look that converted him from a classic 4-3 defensive end into a stand-up outside linebacker in the 3-4.
Despite his diminutive stature — 5-foot-11 and 248 pounds — Dumervil possesses long arms and a low center of gravity, making him difficult to defend.
He has 43 sacks since being drafted in the fourth round out of the University of Louisville in 2006.
The 26-year-old Dumervil was anticipating another big season, too, joking around before camp began about the pressures of trying to defend his sacks crown.
He was actually looking forward to the challenge.
Dumervil also admitted his new deal with the team took weight off his shoulders.
AP Sports Writer Arnie Stapleton contributed to this story.