Coach Mike Sullivan said Tuesday that Lovejoy is dealing with a "long-term" upper body injury and is out indefinitely. Lovejoy, 32, left last Saturday's loss to Tampa Bay midway through the second period following a collision with Lightning forward J.T. Brown.
Sullivan declined to give a timetable for Lovejoy's possible return. Lovejoy has three goals and six assists in 57 games for the Penguins this season and has a plus/minus of plus-9, second among defensemen on the team.
Injured forwards Evgeni Malkin and Nick Bonino practiced on Tuesday but will not be in the lineup when Pittsburgh plays at Boston on Wednesday. Malkin hasn't played since Feb. 2, and Bonino has been out since Jan. 12.