The 27-year-old has missed a combined 30 games to injury heading into the Bruins' game against the Washington Capitals on Thursday.
An injury to the quad has kept him out of the lineup since Jan. 19. He had finally resumed skating and was very close to a return after the Olympic Break before re-aggravating it.
Boston acquired defenseman Andrej Meszaros from the Flyers for a conditional pick in this year's draft and claimed Corey Potter off waivers from Edmonton on Wednesday, in part to alleviate the effects of McQuaid's absence, along with Dennis Seidenberg's season-ending ACL tear and surgery.
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