Mantha was injured in the third period during a 4-1 loss at the Toronto Maple Leafs on Saturday when he was hit to the ice by defenseman Jake Muzzin. He did not play Sunday in a 5-2 home loss to the Arizona Coyotes.
Coach Jeff Blashill said after the game against Toronto that he hoped Mantha would be ready to return after the Christmas break, but said after practice Friday that the 25-year-old would be out for "a minimum of four weeks".
"He's got what I'd call rib-type issues and things associated with that," Blashill said. "It's not the head or anything like that or anything that would preclude him from having a long and real good career. But he's going to be out for a good stretch."
The injury came in Mantha's fourth game after returning from a knee injury that kept him out for eight games.
Mantha is second on the Red Wings in goals (12) and points (24). He scored an NHL career-high 25 goals in 67 games last season, missing a month because of a broken hand.
The Red Wings are 9-26-3, last in the NHL, entering their game at the Florida Panthers on Saturday (7 p.m. ET; FS-F, FS-D+, NHL.TV).
