Giroux faces a potential suspension for the head shot he delivered to Zubrus, one that earned him a minor penalty for an illegal check to the head late in the second period.
Zubrus returned for the third period and scored an empty-net goal for the Devils, who took a 3-1 series lead.
"For me it looks textbook, like the hits they're trying to get out of the game," Devils coach Peter DeBoer said following the game. "But I understand (NHL commissioner) Gary Bettman and (deputy commissioner) Bill Daly were here, and I'm sure they'll look at that."
Should league disciplinarian Brendan Shanahan suspend Giroux, the Flyers will be without their best player while facing elimination in Game 5 in Philadelphia on Tuesday.
The 24-year-old has eight goals and nine assists in 10 games this postseason.