TORONTO -- The Toronto Maple Leafs will be without No. 1 goaltender Jack Campbell for at least the next two weeks because of a rib injury, coach Sheldon Keefe said after Thursday's morning skate.

Keefe said the 30-year-old Campbell "tweaked something" a while ago and then aggravated the issue during a 26-save performance in Tuesday night's 6-4 victory over the Seattle Kraken.

"I knew that he was uncomfortable after the game, and (Wednesday) wasn't feeling a lot better," Keefe said. "They sent him for some tests and ultimately found out he needs some time."

Campbell had an excellent start to the season to earn his first All-Star nod but has an .865 save percentage since mid-January.

Petr Mrazek, who signed a three-year contract in free agency in July, will take over in goal. Mrazek, who had a tough start to his tenure with the Maple Leafs after twice being felled by a groin injury, has a 10-5-0 record this season with an .890 save percentage.

The Leafs have recalled Erik Kallgren from the AHL's Toronto Marlies on an emergency basis. The 25-year-old Swede has a 15-8-1 record with a .904 save percentage in his first campaign with the Marlies. He's expected to serve as Mrazek's backup Thursday against Arizona.