INDIANAPOLIS -- The Indianapolis Colts have survived most of this season without their best defender, safety Bob Sanders.
Now they'll have to fight their way into the playoffs without their defensive captain.
Middle linebacker Gary Brackett is expected to miss at least two games with a cracked bone in his lower right leg, and coach Tony Dungy gave a surprise Wednesday when he announced seldom-used Buster Davis would likely replace Brackett in the lineup this week against Cincinnati.
"Our hope is that it will be short term and we'll fight through it, till we get him back," Dungy said. "Your middle linebacker is kind of like your quarterback, so it's like losing a quarterback. He (Brackett) has been our leader."
But Dungy provided some hopeful news when he said Sanders could return this week. Last season's NFL defensive player of the year has missed the last three games with swelling in his right knee, the same knee he had surgery on this season when he missed five straight games with a high ankle sprain.
Dungy has said the swelling is not related to the surgery.
"Bob went through the walkthrough today and said he'll be fine," Dungy said. "We'll have to wait and see."
Brackett, though, has been one of the stabilizing forces on a defense that has made steady progress this season.
But his impact can't be measured merely by his team-high 113 tackles or his unflappable demeanor. He wears the radio helmet, makes all the defensive calls and is responsible for getting players lined up in the right places on each play.
Brackett also has been one of the Colts most dependable players, having started all 12 games this season and 58-of-60 since wresting the starting job from Rob Morris in 2005. This is his fourth straight season with at least 100 tackles, and he's been a regular staple in the Colts' nickel and dime packages.
Davis, who hasn't played in a game since Week 3, now has to replace the continuity, knowledge and experience that has turned Brackett into such a valuable part of the team's defense. Davis was signed by the Colts in September after being waived by the Detroit Lions, and he's been inactive for eight of the last nine games.
"He's a powerful guy and he's done a good job on the looks squad," Dungy said. "He is our next middle linebacker and he was not active Sunday, so Freddy Keiaho played there. We'll see how practice goes, and if he has problems, we'll put Freddy in there."
If things don't go well, Dungy could improvise by moving Keiaho, the Colts' third-leading tackler with 92, to the middle and inserting Tyjuan Hagler on the outside. Hagler started seven games last year but was on the physically-unable-to-perform list until mid-October after tearing a pectoral muscle in July.
Brackett's absence is yet another blow in an injury rash that has sabotaged the Colts' goal of winning a sixth straight AFC South title.
"It's a big loss," defensive end Robert Mathis said. "He's our captain, he gets everybody in position. But the next guy just has to step up."
Copyright 2008 by The Associated Press