Santa Clara, CA (SportsNetwork.com) - The San Francisco 49ers activated nose tackle Glenn Dorsey from the injured reserve/designated to return list on Monday.

Dorsey was placed on the short-term IR in early September, after reportedly tearing his biceps during a practice session early in training camp.

A 13-game starter for the NFC Championship Game participant 49ers last season, Dorsey joins a Niners club tied for the third-fewest points allowed in the NFC with 212 after 10 games.

Dorsey had been the third key defender for San Francisco to start the year on the sidelines. All-Pro inside linebacker NaVarro Bowman is recovering from a torn ACL suffered in January's NFC title game, while standout pass rusher Aldon Smith was handed a nine-game suspension for violations of the league's substance abuse and personal conduct policy.

To make room on the roster, San Francisco placed nose tackle Ian Williams on season-ending injured reserve. Williams set a career best with 41 tackles and one sack over nine games (eight starts) in 2014.