The Giants defensive end was fined $20,000 by the NFL on Wednesday, a few hours after he missed a mandatory morning media session.
"I misunderstood the schedule," Umenyiora said in a statement released by the team. "It won't happen again, and I will be at tomorrow's media session and available after the game. I apologize for any inconvenience my absence this morning may have caused."
Umenyiora was supposed to be sitting at a riser answering questions after coach Tom Coughlin spoke, but his seat remained empty for the 45-minute session. The league announced its fine less than two hours later.