Peca underwent surgery Sunday to repair a broken right leg and will be sidelined for up to four months.
Peca, 32, suffered the injury late in the first period of Friday's 3-1 loss to Chicago when he collided with Blackhawks defenseman Jim Vandermeer, who received a five-minute major penalty and a game misconduct.
"My legs were together and I turned out of the way," Vandermeer said. "We did hit knee on knee, but it was more him trying to get out the way than me throwing something out there to hit him."
Toronto general manager John Ferguson said Peca had surgery Saturday to repair a broken tibia at the base of his right knee.
After helping the Edmonton Oilers win the Western Conference title last spring, Peca has four goals and 11 assists in 35 games with the Maple Leafs this season.
A 12-year veteran, Peca's best season was in 1998-99, when he had 27 goals and 29 assists with Buffalo. He has also played with Vancouver and the New York Islanders.
"It's tough when you see a guy [Vandermeer] who can barely play in this league take out one of the best players in this league," Toronto center Jeff O'Neill said. "I don't know if he meant to do it or not, but this sucks for us."
Toronto coach Paul Maurice was not very happy with what transpired.
"The play happened on the other side of the ice, and I didn't get a good look at it," Maurice said. "I do know it was a knee-on-knee hit. Our guy will be out a long time and their guy will probably be in the minors by the time our guy gets back."
To replace Peca on the roster, the Maple Leafs recalled left wing Kris Newbury from the Toronto Marlies of the American Hockey League.