SAN FRANCISCO — San Francisco 49ers nose tackle Glenn Dorsey has a torn left biceps muscle and will undergo surgery, a person with knowledge of the injury said Saturday.

It’s unclear how long he might be sidelined, though reported Dorsey will miss the season.

Another source said it would be premature to speculate that Dorsey will miss the entire 2014 season as more evaluations still must be done.

The Niners had a day off from training camp Saturday.

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Losing Dorsey would be a huge blow 11 months after 2013 starting nose tackle Ian Williams went down with a season-ending ankle injury in a Week 2 loss at Seattle. Dorsey quickly emerged as a reliable replacement and stabilizing force for the defensive line.

Williams has undergone multiple surgeries and is on the physically unable to perform list.

The Niners, however, are deep on the defensive line. Mike Purcell, an undrafted free agent last year, could be an immediate option to fill the void. Second-year player Quinton Dial, a fifth-round pick out of Alabama last year, also is an option.


Drew Brees stood on the sideline throughout the Saints’ first scrimmage of training camp, resting a strained abdominal muscle on his left side and likely watching with envy as his backups cashed in on the big-play potential of rookie receiver Brandin Cooks.

• Cleveland Browns rookie quarterback Johnny Manziel returned to campus in Akron, Ohio, and showed flashes of the improvisational wizard who took college football by storm the past two years at Texas A&M, resulting in a Heisman Trophy.

• Quarterback Sam Bradford showed improved zip on the ball during the St. Louis Rams’ fan fest scrimmage at the Edward Jones Dome. Bradford seems to be benefiting from improved upper-body strength. To keep the arm strong, coaches are monitoring Bradford’s pitch count much as the St. Louis Cardinals would do for star pitcher Adam Wainwright. There is no set limit for Bradford, but he is monitored closely.