Pettersson (lower body) was activated off injured reserve by the Penguins on Tuesday, per the NHL media site.
Pettersson hasn't suited up since Dec. 14 due to a lower-body injury, but he should be back in action for Tuesday's road game against Detroit. Prior to his six-game absence, Pettersson had racked up two goals, 13 points, 56 blocked shots, 36 hits and 21 PIM while averaging 21:47 of ice time over 32 appearances this season.