The busiest man at the Denver Broncos' training camp so far has been head trainer Steve Antonopulos.

In the week since the Broncos started camp, they've lost their top two tailbacks, the NFL sacks leader from last season along with his primary backup and their right guard who was the team's only returning starter along the battered offensive line.

The most devastating of the Broncos' injuries is the torn chest muscle that Elvis Dumervil suffered Wednesday while blocking Tyler Polumbus in a 1-on-1 drill.

Dumervil, who signed a $58.332 million extension just two weeks ago, is expected to miss up to five months, effectively ending his season and forcing the Broncos to reconsider their 3-4 alignment in favor of the 4-3 so they can take advantage of their depth on the defensive line and make up for their bad luck at linebacker.

Dumervil led the league with 17 sacks last season, when Robert Ayers and Jarvis Moss had zero. In just his second practice since replacing Dumervil in the starting lineup, Moss broke his right hand Friday. He'll need surgery to fix the break and will likely miss two weeks of practice.

Right guard Chris Kuper (ankle) and newly acquired tailback LenDale White (apparent leg injury) also got hurt Friday.

The Broncos' misfortunes actually began in the offseason when All-Pro left tackle Ryan Clady injured a knee while playing a pickup basketball game and required surgery. Special teams star Darrell Reid had radical knee surgery this year, too.

Midway through the first practice of training camp, tailbacks Knowshon Moreno (hamstring) and Correll Buckhalter (back) went down minutes apart.

The trips to the trainer's room haven't slowed down since.

Not counting Clady and Reid, 13 players, including star linebacker D.J. Williams and Pro Bowl safety Brian Dawkins, have missed time at camp so far for medical reasons and two players — wide receiver Kenny McKinley and safety Josh Barrett — have suffered season-ending injuries.

"It happens from time to time," Dawkins said. "You know, obviously, this is my 15th year in the league and I've had camps similar to this in Philadelphia. You hate it when it happens and you hope it stops pretty soon and nobody else goes down. Those guys that step in have to just step up and we all collectively have to do a better job."

Coach Josh McDaniels can't put his finger on why the Broncos have been the most snakebit team in the NFL this summer. Last year, they made it through camp healthy and started the season 6-0.

"We didn't change our conditioning program from one year to the next, we didn't change the way we get ready for practice, we didn't change our stretching routines or anything like that," McDaniels said. "It's just sometimes I think those are freak things that happen. I think our job is just to manage them the best we can and handle them and move forward and try to keep getting better."

McDaniels took his players out of pads Friday night and canceled the morning practice Saturday but still planned for a full-pads, hard-hitting open workout in the evening at Invesco Field.

"Obviously, we're not going to put players out here that we would risk injuring further and we'll try to monitor and manage everybody the best we can so that we're ready to go for September, while still trying to get better out here," McDaniels said.

Dumervil's injury is the most devastating to the Broncos. Not only do they lose his ballyhooed bull-rush and playmaking ability, but his loss means several of his teammates will have to shift around and play in spots they weren't expecting to.

Linebacker Akin Ayodele looked at the bright side: at least Dumervil went down early in camp, "and guys can get reps," he said.

The pressure is now on every other defensive player to put pressure on the quarterback.

Of the 39 sacks the Broncos racked up last season, 35 of them were recorded by players either hurt or no longer on the team. And of those four remaining sacks, three came on blitzes by defensive backs.

The Broncos beefed up their defensive line through free agency and the centerpiece of that rebuilding project was 13-year veteran nose tackle Jamal Williams, who missed most of last season with a triceps injury.

He sat out most of the first week of practice, although McDaniels refused to say whether it was for physical or fitness reasons. By the time he finally got on the field, Dumervil was gone and the Broncos' defensive front seven was a mosh pit of bodies.

And their misfortune hasn't been limited to the playing field.

Adding insult to their rash of injuries: the Broncos lost Barrett (shoulder) to the New England Patriots, who claimed him during the 24-hour waiver period before he could go on Denver's injured reserve list.