And other than the Broncos' bandaged backfield, nowhere have their injuries had a bigger effect than on special teams. Because, in many ways, a team's special- teams units are the rainy-day fund. And, this season, the Broncos have used up plenty of their vocational savings.

"When they need a guy on offense or defense, they're coming to special teams," Broncos long snapper Mike Leach said.

"That's where you get affected the most is on special teams," coach Mike Shanahan said. "Lose a starter, and usually the backup players are the specialists. So they move into a new role as a starter, and now somebody else has to come in on special teams.

"But if that player who's now a starter plays on three or four special-teams units, now you're talking about filling three or four spots because of one thing that happened on offense and defense."

So, do the math. The Broncos have had far more than one or two things happen on offense. They have 14 players on injured reserve, having moved running backs Selvin Young and P.J. Pope there Monday.

And six of those players have started games this season.

That has put Scott O'Brien, the Broncos' special-teams coordinator, into mix- and-match mode on a week-to-week basis.

So much so that O'Brien said he couldn't even hazard a guess how many combinations he has played this season. Tight end Jeb Putzier played on two of the special- teams units against Buffalo, and Putzier had signed only two weeks earlier.

Safety Herana-Daze Jones also played on special teams against the Bills, and he had signed only a week earlier.

When tight end Nate Jackson went to injured reserve with a hamstring injury last month, he had played on all the Broncos' kickoff- and punt-coverage units. And the Broncos simply couldn't move another tight end, like Chad Mustard, into Jackson's position because Mustard already was on some special-teams units and, besides, Jackson is faster, so he plays a different role.

So it took more than one player to cover just Jackson's special-team slots.

When the Broncos were down to one running back against Kansas City after Peyton Hillis' hamstring injury, they had to take Tatum Bell off special teams to play only offense for the remainder of the afternoon and, thus, found themselves trying to fill Bell's slots on the fly.

Shanahan said the situation even has affected how the team arranges the depth chart for practices during the week and made it more difficult to decide which 45 players will be in uniform on game day.

"That's a ripple effect and the ripples get bigger every time it happens," Shanahan said. "Usually you've got an idea on Tuesday what your 45 is going to look like, so you can figure out how you're going to put people in position to practice, who's going to work with the starters for the week. But this year it's been a little different - there have been more question marks through the week about who is going to be able to play.

"So, instead of either this guy or that guy, it's been an or, or, or kind of deal."

It's significant for a team such as the Broncos, who have so many first-year players. Often, a player good enough to make the jump from college to the NFL had not been asked to play on special teams because of his standing on his college team.

So the learning curve can be steep, especially in terms of maintaining discipline in coverage.

"It takes a little time for guys to get good on special teams," Shanahan said. "So you're always kind of juggling what personnel can play what percentage of the time."

It's also significant this week, with the AFC West title on the line at San Diego, because awaiting the ball on punts and kickoffs likely will be Chargers running back Darren Sproles.

And Sproles is a king-sized problem in a 5-foot-6 package. The Broncos were leading 21-3 in the teams' Sept. 14 meeting at Invesco Field at Mile High when Sproles returned a kickoff 103 yards for a touchdown to pull the first thread that unraveled the Broncos' effort.

Sproles also opened the second half with a 41-yard kickoff return, and eight plays later, San Diego had another touchdown that cut the Broncos' lead to seven with more than 11/2 quarters to play.

"We have the effort, and we haven't had breakdowns . . . more often because somebody's been new," Leach said. "But absolutely we've had more turnover out there this year, and it only takes one guy to be out of position for something bad to happen.

"But there are no excuses, though - who's ever in there has to perform. That's the expectation this week and every week."

ETC.: The Chargers are 8-0 in December games under Norv Turner. That total includes five wins in December last season to go with the team's current three-game winning streak. . . . Chargers nose tackle Jamal Williams has a sprained foot and could miss some practice time this week, but he is expected to play Sunday. . . . The Broncos on Tuesday officially signed running back Cory Boyd to their active roster from the practice squad and also signed running back Alex Haynes. Haynes had been with the team for two weeks in November.

INFOBOX

Make a list

The Broncos have faced four of the NFL's top 10 kickoff returners this season and six of the top 10 punt returners.

*NFL Kickoff returners Avg. rank

Leodis McKelvin, Bills 28.7 2

Ellis Hobbs, Patriots 28.5 3

Darren Sproles, Chargers 26.1 7

Leon Washington, Jets 25.9 9

*NFL Punt returners Avg. rank

Roscoe Parrish, Bills 15.3 1

Reggie Bush, Saints 13.5 3

Johnnie Lee Higgins, Raiders 12.6 4

Darren Sproles, Chargers 11.7 8

Mark Jones, Panthers 11.6 9

Davone Bess, Dolphins 10.8 10