ORCHARD PARK, N.Y. -- When Buffalo's Takeo Spikes sat on the field in pain and slammed his helmet to the ground, everyone knew something was wrong. When the two-time Pro Bowl linebacker had tears in his eyes while carted to the training room, everyone knew it was serious. Spikes, who has never missed a game due to injury in his seven-plus NFL seasons, is out for the year with a torn right Achilles' tendon. The injury happened in Buffalo's 24-16 loss to Atlanta on Sunday and leaves the Bills without their top defensive player and the unit's inspirational and physical leader. "It's a big blow for our defense," linebacker London Fletcher said Monday. "However, we will still play football on Sunday. Injuries happen all the time. We've got some other guys that have to take up the slack." The Bills (1-2) prepare to play the New Orleans Saints at San Antonio on Sunday. "It's devastating," safety Troy Vincent added. "But we can't lose the swagger. ... We're just going to have to pick up the pieces and keep rolling. No player wants that to happen to them, but that's part of the game." Coach Mike Mularkey said Spikes will have surgery. He added team doctors informed him Spikes should fully recover. "It's hard to replace a player of his caliber, but we're looking at this as an opportunity for another good player to step up and fill his shoes," Mularkey said. "I think it might be a motivation for us. If anything, they might even want to play even harder for him." Third-year veteran Angelo Crowell will make his first career start replacing Spikes. Spikes was hurt in the second quarter while pressuring quarterback Michael Vick. It's unclear what happened on the play, but Spikes was left lying face down on the field a few feet in front of Vick, who had overthrown receiver Roddy White. After being carted to the training room, Spikes addressed the team at halftime, giving what teammates described as an emotional speech. "You felt his emotion and you could appreciate it. It was sincere," Vincent said. "And if nothing else, he wasn't out on the field with us physically, but emotionally and spiritually you could feel his spirit." The Bills responded when Chris Kelsay intercepted Vick's pass on the Falcons first possession of the second half. But it wasn't enough to prevent Vick from securing Atlanta's victory with a nine-play, 65-yard drive, capped by T.J. Duckett's 12-yard touchdown run early in the fourth quarter. Buffalo's defense has struggled this season even with Spikes in the lineup, allowing a combined 721 yards in its last two games, including a 19-3 loss at Tampa Bay on Sept. 18. That's uncharacteristic for a veteran unit that returned mostly intact this year and allowed the second fewest yards in the league in each of the last two seasons. Spikes has only missed one NFL game -- in 2001 -- to attend his father's funeral when he was with Cincinnati. He's in his third season with Buffalo after the Bills lured him from Cincinnati in March 2003, signing the former first-round draft pick to a six-year $32 million contract, a deal the Bengals had the right to match, but declined. Last year, Spikes' five interceptions were the most by a Bills linebacker since Darryl Talley had five in 1991. "He wouldn't want us to worry about him too much. That's just the type of guy he is," safety Lawyer Milloy said. "It's the teams that don't sit there and say, `Woe is me.' ... Now's the time for the young guys to do a little more and help fill that void." Crowell, Buffalo's 2003 third-round draft pick, has played mostly on special teams. He was in on six tackles replacing Spikes against Atlanta. "You hate to lose a guy like Takeo Spikes, but it's just a time for me to step up, make the plays he was making and get this defense back on a roll," Crowell said. "It is mixed emotions. But I believe he'd definitely want me to step up, replace him and get the job done."