Linus Ullmark was unable to finish his start on Monday.
The Ottawa Senators goaltender left after the second period against the Boston Bruins due to a collision with JJ Peterka.
The Bruins forward collided with Ullmark near the end of the second when he was tripped on a rush.
"He kind of tweaked something a little bit," head coach Travis Green told reporters post-game. "Precautionary, we just felt it was best if we bring him out. Get it evaluated again."
Samuel Ersson, making his Senators debut, took over the crease for the final 20 minutes. Ullmark did eventually return to the bench during the final frame.
Prior to exiting, Ullmark stopped all 10 of the shots he faced. He also made 27 saves on 29 shots in the Senators' season-opening win over the Toronto Maple Leafs on Saturday.
Ullmark missed a good chunk of last season due to personal reasons, but had a 2.73 GAA and .891 save percentage in 49 appearances.
