In the statement announcing the move, the team said Pietrangelo would be re-evaluated in three weeks.
Pietrangelo has three goals and 20 assists in 55 games this season. He's fourth in the NHL in playing time, averaging over 26 minutes.
"It's a huge [loss]. You never want to lose anybody, but he plays close to 30 minutes a night," goaltender Brian Elliott said in a release on the team's website.
The Associated Press contributed to this report.