PITTSBURGH - The Pittsburgh Steelers had plenty of excuses for losing this season: Kendall Simmons' knee and Kendrell Bell's oft-injured groin. Chad Scott's knee and Plaxico Burress' thigh. Tommy Maddox's elbow and Casey Hampton's knee.

So much for excuses. So much for losing.

Through all the injuries - and nearly half their starters have gone down at some stage of the season - the Steelers (14-1) have built a 13-game winning streak that is the longest in the franchise's 72-season history.

Now, despite two more injuries - quarterback Ben Roethlisberger's sore ribs and cornerback Deshea Townsend's broken hand - the Steelers promise there will be no letting up Sunday at Buffalo (9-6), even though they have little to gain by winning.

By beating Baltimore 20-7 Sunday, the Steelers assured themselves home-field advantage throughout the AFC playoffs and a first-round bye the weekend of Jan. 8-9. As a result, their main incentive against Buffalo is to go 15-1 for the first time in franchise history and better the previous franchise-best record of 14-2 in 1978.

Coach Bill Cowher has frequently rested his regulars during meaningless late-season games in other seasons, but doesn't seem as inclined to do so now. That could be good news for the Broncos, Jets, Jaguars and Ravens, all of whom might need a Bills loss to get into the playoffs.

"We are playing too well to go up there and not win that football game," Cowher said. "It's not so much the record (15-1) as much as it is that we keep playing well."

Even if they haven't been totally well since the first week of training camp, when Simmons, their right guard and former first-round draft pick, went down with a season-ending knee injury.

But, rather than caving in amid numerous injuries as they did during a 6-10 season a year ago, the Steelers seemingly have rallied around them. Linebackers Larry Foote and James Harrison, cornerback Willie Williams, guard Keydrick Vincent, defensive lineman Chris Hoke - and, yes, Ben Roethlisberger and Jerome Bettis, too - have gotten far more playing time than projected, and none one has been a disappointment.

"We're winning with a lot of guys hurt," linebacker Joey Porter said. "Now we're going to get those guys back for the playoffs. Having a healthy Duce Staley, a healthy Jerome Bettis is priceless. We'll have a healthy Plaxico Burress and a healthy Hines Ward and a healthy Antwaan Randle El, a healthy Clark Haggans. Anybody who's hurt is going to have a a chance to get healthy."

For now, the Steelers' most immediate concern is Roethlisberger, who injured his ribs Sunday while being driven to the turf by Baltimore's Terrell Suggs. Roethlisberger had precautionary tests on his ribs, spleen and sternum, but the team will not comment on his condition until Cowher's weekly news conference today.

The Steelers don't seem overly concerned about his condition - Cowher has not ruled out playing Roethlisberger on Sunday - because they have nearly three full weeks before they play their next meaningful game.

If Roethlisberger can't go Sunday, Maddox will make his first start since he injured his right elbow Sept. 19 at Baltimore, thus making Roethlisberger the starter by default. If Roethlisberger doesn't play, his 13-0 record as a starter will go down as the best in NFL history by a rookie quarterback.

"We recognize that the next season is the playoffs, and that's what we're going to gear ourselves for," Cowher said.