Ottawa Senators center Jason Spezza will be sidelined indefinitely due to impending back surgery.

Spezza missed the last two games with an upper body injury, and speculation as to the severity of the issue only surfaced on Thursday, as the Sens posted a 5-1 home victory over the Montreal Canadiens. Multiple reports state that the issue is a herniated disc.

"Jason Spezza is out indefinitely," said Senators general manager Bryan Murray Thursday on the team's Twitter account. "Will have back surgery in Toronto on Friday."

In five games this season, Spezza has two goals and three assists. He is coming off a 34-goal, 84-point season in 2011-12.