BOSTON -- Boston Bruins leading scorer David Pastrnak left Monday night's game against the Washington Capitals in the second period due to an undisclosed upper-body injury and did not return.

Bruins coach Joe Sacco provided few details on the condition of the 28-year-old forward after the 4-1 victory over the Capitals.

"I'll get more details on that either later tonight or tomorrow," Sacco said.

Pastrnak skated away gingerly after a seemingly innocuous collision with Capitals forward Tom Wilson about three minutes into the second period. He appeared uncomfortable on the bench but briefly returned to the ice before heading to the locker room.

The team announced during the third period that he was "unlikely to return," and he did not.

A three-time All-Star who tied for the most goals in the NHL in 2020, Pastrnak had 12 goals and 23 assists in the Bruins' first 35 games this season.