WILMINGTON, Mass. — The Bruins were without defenseman Johnny Boychuk as expected at practice on Monday.

He’ll miss four weeks after suffering a fracture in his left forearm from a slash in Saturday’s game with the Rangers.

But the Bruins were also missing a key forward for Monday’s workout at Ristuccia Arena, as center David Krejci was also absent.

Krejci has his own checkered past when it comes to injuries, as the 24-year-old fifth-year pro has already underwent hip surgery, suffered a dislocated wrist and even battled a bout of the swine flu in his young career. He went under the knife again on Monday, but fortunately this time it’s not nearly as serious a matter.

Krejci needed to have his wisdom teeth removed, forcing him to miss the practice. Barring any complications, he should be fine to play in Boston’s next game when they host Toronto on Thursday.

Everyone else was present for practice, including forwards Milan Lucic and Greg Campbell. Lucic needed three stitches to close a cut suffered in a fight with New York’s Brandon Prust on Saturday, while Campbell took a couple of stitches in the back of his head after taking a puck off the helmet when he went down to block a shot.

“Obviously it didn’t feel that good,” said Campbell after the game. “But it’s a big game and I’m not going to sit aside and watch. I wanted to come back and help.”

Campbell passed verbal and memory tests before returning to finish the game on Saturday, while Lucic also played the rest of the contest after getting stitched up.

With Krejci out, Daniel Paille, a healthy scratch the last five games, moved up to the top line to center Lucic and Nathan Horton in drills during Monday’s practice. The rest of the forward line combinations remained the same, with Patrice Bergeron between Blake Wheeler and Jordan Caron, Tyler Seguin centering Mark Recchi and Michael Ryder and Campbell skating with Shawn Thornton, Brad Marchand and Brian McGrattan.