With captain Mikko Koivu already sidelined during the most critical juncture of the season, Cal Clutterbuck missed Sunday's 3-2 overtime loss to Buffalo with what the Wild is calling an "upper body" injury.

GM Chuck Fletcher and coach Todd Richards wouldn't identify the injury or guess how long he will be out. But Clutterbuck has not been feeling well since being hit in the head by the Islanders' Trevor Gillies on Wednesday night.

Gillies was suspended 10 games for the infraction.

Clutterbuck played the next night against the Rangers, but before that game, he didn't sound convinced he was scot-free.

"What if for some reason in a couple days I get [concussion-like] symptoms and I have to miss time where it's really important for our team?" Clutterbuck said Thursday.

The Wild has not classified Clutterbuck's injury as a concussion. He would have to miss at least a week if that were the case. But even though he finished the Islanders game and played the Rangers, concussion symptoms often crop up after the fact.

Sidney Crosby played one game after being hit in the Jan. 1 Winter Classic, but he hasn't played since. In October, Antti Miettinen finished a game in which he was hit in the head by Los Angeles captain Dustin Brown. But Miettinen missed the next five games with a concussion.

Clutterbuck, at the game, was not permitted by the team to talk to the media. The Wild is 6-7-1 all-time without Clutterbuck, the NHL's hits leader and team's second-leading goal scorer (18).

"Right now it's one of those things where we have to find a way," Richards said.

Against Buffalo, the Wild got energy and physicality from fourth-line grinders Warren Peters, 28, a minor league journeyman who used to captain WHL Saskatoon and AHL Quad City, and Brad Staubitz.

Staubitz and Peters helped change the momentum by teaming up for Peters' third career goal. That trimmed a 2-0 lead in half.

"I don't think you can make up for the amount of hits that [Clutterbuck] has on a regular basis," Peters said. "I'm just trying to contribute, and I think playing physically is something that's probably expected from me and it's a way I'm going to earn minutes."