San Francisco 49ers nose tackle Glenn Dorsey needs surgery to repair his torn his left biceps muscle and could be out for the entire 2014-15 season.

The Associated Press reports that Dorsey left the team's practice on Friday with the injury, and that sources could not tell if its a season-ending injury. But ESPN.com is also reporting that sources within the 49ers camp confirm that the team has lost the middle guard for the upcoming season.

The team took a day off from training camp on Saturday.

Dorsey's injury will have a huge impact on the team's chances this season. Dorsey had emerged as a reliable replacement to starting nose tackle Ian Williams who suffered a season-ending injury almost a year ago.

Coach Jim Harbaugh had even raved about Dorsey's contributions last year, telling AP: ''It's been A-plus, plus. What a great thing having him last year. Fit in so seamlessly with that group of talented defensive lineman. Was a great contributor, a starter for us. Known friend and trusted agent. Just thank him for being good, thank him for being who he is and how he goes about his job. He's a team guy all the way.''

Dorsey was signed by the Niners in March 2013 to a two-year deal that could give him up to $7 million with incentives. He got the starting nose tackle job after Williams went down with an ankle injury in a game against Seattle.

The injury is a pity considering that Dorsey was getting much success with the Niners after five relatively unsuccessful seasons with the Kansas City Chiefs, which drafted him No. 5 overall in 2008.

With Dorsey out, who should step up for the Niners? Tell us @SportsWN.