Karlsson (undisclosed) left Game 4 after two periods, Dan Rosen of NHL.com reports.

EDGE Analysis

The Swede has been dealing with hairline foot fractures throughout the playoffs, so that is likely the culprit, but the team hasn't said whether that is or isn't the cause. It could be much needed rest in a blowout, or it could be something more serious, so expect more news before Game 5 on Saturday.