Senators forward Jason Spezza will have back surgery Friday to repair a herniated disk, according to an ESPN.com report.

Senators GM Bryan Murray said it's too early to give a timeline for Spezza's return, but the team is hopeful he'll be play again this season.

Rangers captain Ryan Callahan will miss 10 to 14 days with a partially dislocated shoulder suffered Tuesday night against the Flyers, the team announced Wednesday.

Callahan was examined by Dr. Andrew Feldman and underwent an MRI on his left shoulder Wednesday.

Rangers captain Ryan Callahan left Tuesday's 2-1 win against the Flyers after suffering an apparent arm injury during a third-period fight with Maxime Talbot.

There was no immediate medical update regarding Callahan after the game.

Coach John Tortorella said he had "no idea" how long the injury would sideline Callahan.

Canadiens forward Max Pacioretty will miss three-to-four weeks after having an emergency appendectomy, according to an ESPN.com report on Saturday.

Flyers GM Paul Holmgren said Friday that winger Scott Hartnell had successful surgery to repair a broken first metatarsal in his left foot and will be out four to six weeks, according to an ESPN.com report.

Flyers GM Paul Holmgren announced on Wednesday night that the team will be without Scott Hartnell indefinitely because of a left foot injury, according to an ESPN.com report.

"We will know more on this within a day or two as we await results of tests," Holmgren said in a statement released by the team.

Maple Leafs forward Joffrey Lupul fractured his forearm in Wednesday night's 5-2 win over the Penguins and is out indefinitely, according to an ESPN.com report.

Coach Randy Carlyle said Lupul will be re-evaluated on Thursday before the team returns home to face the Islanders.

 The Avalanche announced today that forward Steve Downie will undergo season-ending knee surgery to repair a torn anterior cruciate ligament.

Downie, 25, suffered the injury during Tuesday night’s 3-1 victory over the Kings at Pepsi Center.

The headaches that plagued Sidney Crosby and robbed hockey's best player of nearly two seasons have disappeared.

The Penguins star captain no longer worries about how he'll feel when he wakes up in the morning. The doubts about whether he's really healthy after dealing with concussion-like symptoms for all of 2011 and parts of 2012 are long gone.

It's been nearly a full year since Bruins forward Nathan Horton has played in an NHL game after suffering his second concussion in a seven-month span on Jan. 22, 2012.

On Thursday, he was back on the ice with his teammates during an informal practice as the Bruins prepare for a seven-day training camp beginning on Sunday, according to an ESPN.com report.