Bryan Rust has a concussion and is out indefinitely for the Pittsburgh Penguins.
The forward was injured on a hit into the end boards by Robert Hagg of the Philadelphia Flyers at 8:28 of the first period of a 5-2 win Wednesday.
Rust has 33 points (10 goals, 23 assists) in 57 games this season, including 14 points (six goals, eight assists) in 17 games since the All-Star break.
"He's a tough guy to replace," Pittsburgh coach Mike Sullivan said Friday. "He's a real versatile player. He's a real good player, brings a lot of energy to our team. I think he helps our team speed when he's in our lineup, so he's not an easy guy to replace."
Penguins forward Dominik Simon is week to week because of a lower-body injury sustained during the second period against the Flyers. He has 12 points (four goals, eight assists) in 31 games.
The Penguins also are missing forward Zach Aston-Reese, who has been out for five games because of an upper-body injury. Sullivan said he's making progress.
Sullivan also said goaltender Matt Murray, who has missed five games because of a concussion, is "making progress and took controlled shots on the ice."
Forward Josh Jooris was recalled from Wilkes-Barre/Scranton of the American Hockey League under emergency conditions Thursday.
The Penguins (39-25-4) are first in the Metropolitan Division, one point ahead of the second-place Washington Capitals and three in front of the third-place Flyers. Pittsburgh plays at the Toronto Maple Leafs on Saturday (7 p.m. ET; NHLN, CBC, SN, CITY, TVAS, ATTSN-PT, NHL.TV).