ORCHARD PARK, N.Y. -- Shawne Merriman's first practice with his new team in Buffalo didn't last very long, and now it's uncertain when the linebacker will play again.

Coach Chan Gailey said Wednesday that Merriman strained his lower right leg and that it's not "anything major," but declined to offer any specifics. Gailey did say the injury makes it less likely Merriman will make his Bills debut Sunday against Detroit.

"Yeah, it hurts him. His chances [to play] go down tremendously," Gailey said of the one-time fearsome pass-rusher whom Buffalo claimed off waivers from San Diego a week ago.

A three-time Pro Bowl selection, Merriman was hurt during an individual drill about 10 minutes into practice. He was dropping back and then pivoting to his left when he pulled up and began hopping on one leg.

Merriman pulled down his right sock and limped to the sideline, where a trainer spent a few minutes checking his ankle. Merriman then consulted head trainer Bud Carpenter at midfield before being escorted to the Bills' fieldhouse, where the team's training room is located.

Merriman's injury was yet another disappointment for a team that's had very little go right this season, and has dropped each of its last three games by three points, including a 22-19 loss to Chicago last weekend.

"It's a tough situation. You don't want that to happen, especially with the excitement he can bring, and what he can do for us defensively," linebacker Paul Posluszny said. "Man, we can't catch a break, but what are you going to do but keep going? We still have to play, we still have to prepare. So we'll continue to press on."

Injuries over the past three seasons have slowed the performance of a player nicknamed "Lights Out" for his hard-hitting style. Merriman's five-plus year career in San Diego ended after the Chargers placed him on injured reserve last month due to a calf injury.

The Chargers waived him once he was ruled healthy.

Merriman passed a physical with the Bills after reporting to the team last weekend, but was wearing a wrap around his left calf during practice Wednesday. He had also been bothered by a right Achilles' tendon injury for much of this year.

He missed most of the 2008 season after undergoing reconstructive knee surgery, and had only four sacks last year after managing 39½ in his first three NFL seasons.

The Bills, off to their worst start in 26 years, were counting on Merriman to spark a defense that's had difficulty generating a pass rush. The team also lost two starters this week when middle linebacker Andra Davis (shoulder) and receiver Roscoe Parrish (broken wrist) were placed on injured reserve Monday.

Gailey was disappointed but not entirely surprised that Merriman might have been stiff in practice, given that he's not practiced for nearly a month.

"What happens is everyone gets their expectations so high, but you've got to realize he hasn't played a lot of football," Gailey said. "He hasn't had pads on in a while, all that kind of stuff. You want him out there, but he's not ready. We're not going to put him out there until he's ready. That's the number one thing."

Before practice, safety Donte Whitner expressed hope that Merriman could start on Sunday.

After practice, Whitner was lowering his expectations.

"Hopefully, we can get him out there as soon as possible," Whitner said. "And he's going to be a big piece for us when he does finally gets out there."

Notes

WR Lee Evans (ankle) was among six regulars who did not practice, but Gailey excepts him to return Thursday. ... CB Terrence McGee is no longer on the team's injury report, meaning he's expected to play Sunday after missing five games because of a nerve problem behind his knee that required surgery. ... Starting RT Cordaro Howard (shoulder) is unlikely to play this week and would be replaced by Mansfield Wrotto, who was signed by the Bills on Oct. 4.