Grzelcyk signed a one-year, $2.75 million contract with the Penguins on Monday, per Elliotte Friedman of Sportsnet.
Grzelcyk had two goals, 11 points, 37 PIM, 53 hits and 76 blocked shots in 63 regular-season outings with Boston in 2023-24. He'll probably serve on the Penguins' third pairing.