The midfielder has returned from a concussion suffered in training.
"My main worry is players burning out by not getting enough rest because that has cost Arsenal over the last couple of seasons," Petit told Lord Ping.
"They've lost some really important players to injury. I think the same thing has happened a little bit this season.
"Odegaard is not the same player as he was last season at the moment.
"He looks a bit sloppy in everything that he is doing, and he looks tired mentally and physically. It's not easy to play every three days and to also play for your country."