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Nose tackle Glenn Dorsey’s injury, which he sustained Friday in practice, is the fourth time since the 2012 season a 49ers defensive player has experienced a torn tendon in the upper arm.
Dorsey is expected to undergo surgery on Monday to repair the damage to the biceps in his left arm. Sources were not ready to rule him out for the entire season, quite yet.
Here's a look at the similar injuries to 49ers' defenders in the past couple of years:
--Last season, defensive lineman Ray McDonald sustained a partially torn biceps tendon Oct. 6 against the Houston Texans. He was removed from that game but did not miss additional games due to the injury. (He sat out two games later in the season with an ankle sprain.)
McDonald required offseason surgery and appears to be close to returning to the practice field.
--Defensive lineman Justin Smith sustained a partially torn triceps tendon late in the 2012 season, forcing him to miss the final 2 ½ games of the regular season. He returned for the playoffs, but was clearly not playing at full strength. He underwent surgery shortly after the 49ers' Super Bowl loss to the Baltimore Ravens.
Smith revealed recently that he was not healthy last season, but that was due to a shoulder injury he sustained in training camp that required offseason surgery.
--Linebacker Parys Haralson was playing on the line of scrimmage in an exhibition game in 2012 against the Denver Broncos when he engaged with a tight end and sustained a torn triceps. Haralson underwent season-ending surgery shortly thereafter.
After the season, coach Jim Harbaugh said the organization regretted not tagging Haralson as “designated to return.” Haralson would have been able to play during the 49ers’ Super Bowl run, Harbaugh said.