"I thought it was pretty cowardly, pretty bush league," Rudolph told reporters postgame, according to ESPN's Brooke Pryor.
"Where did it cross the line? Maybe where he took my helmet off and used it as a weapon," he added.
The incident began during the final seconds of Pittsburgh's loss, when Garrett took Rudolph down following a passing attempt. Teammates immediately came to the quarterback's defense, resulting in Maurkice Pouncey kicking Garrett in the head.
Rudolph insisted he wasn't injured and felt fine after being hit in the head.
The AFC North rivals play each other again in two weeks.