The St. Louis Blues have placed forward Oskar Sundqvist on injured reserve with a lower-body injury sustained during the Blues' 4-3 victory over the Tampa Bay Lightning on Wednesday.

The Sabres' list of injuries continues to grow, with defenseman Rasmus Dahlin out indefinitely with a concussion.

The Sabres also announced forward Vladimir Sobotka is out indefinitely after having surgery on an injured right knee.

Pittsburgh Penguins star Sidney Crosby underwent surgery for a core muscle injury Thursday and is out at least six weeks, the team announced.

General manager Jim Rutherford said the surgery was performed by Dr. William Meyers of the Vincera Institute in Philadelphia. The team said in a statement that Crosby has been dealing with a sports hernia since training camp.

Pittsburgh Penguins star Sidney Crosby missed practice Monday and will not play against the New York Rangers on Tuesday in New York because of a lower-body injury.

"Sid is continuing to be evaluated right now," coach Mike Sullivan said. "I don't have an update for you. He will not play against the Rangers tomorrow. When I get further information, I will let you know."

Toronto Maple Leafs star Mitch Marner will be out a minimum of four weeks after sustaining an ankle injury Saturday against the Flyers.

Marner, 22, is the Leafs' second-leading scorer with 18 points (four goals, 14 assists) in 18 games this season.

St. Louis Blues forward Alexander Steen will miss at least four weeks after suffering a high ankle sprain during Wednesday's game, general manager Doug Armstrong announced Thursday.

Steen left the Blues' 5-2 win over the Edmonton Oilers on Wednesday after an awkward collision with Alex Chiasson late in the second period.

Winnipeg Jets general manager Kevin Cheveldayoff said absent defenseman Dustin Byfuglien has had ankle surgery and the team was not "directly involved" in the decision.

The Jets also announced that forward Mark Letestu will be out at least six months because of myocarditis, an inflammation of the heart muscle.