Coach Mike Sullivan described the injury as longer term and said Murray has been dealing with it for the past couple of weeks.
"This was not something we expected," Sullivan said. "The decision was made this morning to rest and see if that gives him an opportunity to heal."
Murray hasn't played since Nov. 17, when he allowed three goals on 10 shots in a 6-4 loss to the Ottawa Senators before being replaced by Casey DeSmith after the first period. In 11 starts this season, Murray is 4-5-1 with a 4.08 goals-against average, .877 save percentage and one shutout. DeSmith has started Pittsburgh's past two games and is 4-3-3 with a 2.39 GAA and .924 save percentage this season.
Murray also missed time earlier this season after was diagnosed with a concussion on Oct. 9; he didn't play again until Oct. 18.
The Penguins recalled goaltender Tristan Jarry from Wilkes-Barre Scranton of the American Hockey League on an emergency basis later Thursday. He is expected to dress for the Penguins against the Boston Bruins on Friday (7:30 p.m. ET; SN360, SNE, SNO, TVAS, NESN, ATTSN-PT, NHL.TV).
Jarry is 4-5-2 with a 2.89 goals-against average and .909 save percentage in 11 games with Wilkes-Barre/Scranton and scored a goal this season. He was 14-6-2 with a 2.77 GAA and .908 save percentage in 26 games with the Penguins last season.
