Manningham sustained a concussion at the end of the first half, while Hixon suffered a right calf injury.
Hixon made a spectacular 22-yard touchdown catch with 21 seconds left before halftime, extending New York's lead to 21-6. Eli Manning's throw led Hixon past safety Craig Dahl into the end zone. Hixon juggled the ball with his right hand before finally coming down with it as he fell to the ground, but his knee seemed to buckle.
The Giants came into Monday's game already banged up at wide receiver. Hakeem Nicks had a bone bruise on his knee, but he played.
"Are there anymore tight ends in the crowd?," Giants coach Tom Coughlin joked after Monday's game. "We'll get the medical report, we'll do the best we can with it. We have basically six (WRs) now. Hopefully we'll get Mario back. Hopefully he's not too bad. The thing with Hixon is I just don't know what to say about that. I know his confidence was a little bit rattled and I'm hoping that's what it was."
The Giants play at Philadelphia on Sunday.