The Flyers' Blue Line Shuffle - coach Craig Berube has been rotating several defensemen as healthy scratches - will end for the next three weeks.

That's how long Nick Grossmann is expected to be sidelined, general manager Ron Hextall announced Friday.

Grossmann injured his right shoulder when checked into the boards by Washington's Tom Wilson in the first period of the Flyers' 3-2 overtime win Thursday at the Wells Fargo Center.

With Grossmann sidelined, Andrew MacDonald will return to the lineup Saturday afternoon, when the Flyers have a critical matchup against visiting Boston. The Bruins, who are just 8-9-2 on the road, hold the last Eastern Conference playoff spot, and they are nine points ahead of the Flyers.

Among Flyers defensemen, the 6-foot-4, 230-pound Grossmann is second in plus-minus ratings (plus-5), second in goals (three), second in hits (76), and fourth in blocked shots (53).

"He's a big body and he plays big minutes for us," said Nick Schultz, who has probably been the Flyers' most consistent defenseman this season. "It hurts. The good thing is, we have some depth in the back end. . . . Everyone has to step up and try to fill his minutes."

"Obviously he brings a lot to the team," MacDonald said. "He's a big, physical presence; he kills penalties, and he's a smart player."

MacDonald, who signed a six-year, $30 million extension last season, was unhappy about being a healthy scratch Thursday for the second time this season. He and coach Craig Berube had a long chat on the ice during practice Friday in Voorhees.

"He had some things he wanted to say to me, and likewise," MacDonald said. ". . . We're moving on and getting prepared for [Saturday's] game."

At Friday's practice, MacDonald was paired with Mark Streit, Luke Schenn was with Michael Del Zotto, and Braydon Coburn was with Schultz.

Schenn, MacDonald, and Del Zotto have all expressed frustration at being in and out of the lineup this season.

"At the end of the day, it's the coach's decision and we have to live with it," MacDonald said.

"Nobody's saying it's easy," Berube said of his defensive rotation, "but it's part of being a pro."

Goalie Steve Mason is expected to face the Bruins. Mason, who missed four games last month because of back spasms, said that he "tweaked" something during Thursday's win but that he had no problems at practice Friday.

Breakaways. Defenseman Kimmo Timonen, sidelined all season with blood clots, won't know his status until he visits a doctor later this month. . . . Jake Voracek, who leads the NHL with 49 points, and Claude Giroux (45 points, tied for third entering Friday) are expected to be named to the all-star team Saturday.