Grzelcyk (undisclosed) will miss Saturday's Game 7 against Carolina, Fluto Shinzawa of The Athletic reports.
Grzelcyk played the first five games of the series -- going scoreless while averaging 18:09 of ice time -- but sat out Game 6 with his undisclosed injury. If the Bruins advance past Carolina to Round 2, it's unclear when the 28-year-old blueliner might be able to return.