Washington Capitals coach Adam Oates told reporters on Friday that defenseman Jack Hillen will have surgery Friday and will miss "months" after sustaining an injury to his right leg during the team's 5-4 shootout win against the Calgary Flames.

The injury occurred when the Flames' Lance Bouma hit Hillen along the boards 8:10 into the first period.

Hillen was helped off the ice by captain Alex Ovechkin and trainer Greg Smith, and was taken to an area hospital.

It's the second straight season Hillen has sustained a serious injury in an early season game. Last season he missed 25 games after hurting his left shoulder in the season-opener.

"I don't believe it's career-threatening. I still don't know the full extent of the injury," Oates said.

"He's going to be out an extended period of time. It's a tough break for him, two years in a row."

Hillen's absence could open the door for Steve Oleksy, who was a healthy scratch the first two games, or 22-year-old Alexander Urbom, who was claimed off waivers from the New Jersey Devils on Thursday.

Oates admitted Hillen would be out for some time, but stopped short of saying his season was over.

"I wouldn't say that right now," Oates said when asked if Hillen would miss the remainder of the season. "I think it's too early to tell, but it's going to be an extended period of time."