San Francisco nose tackle Ian Williams is expected to be sidelined for the remainder of the season with a broken left ankle. He was undergoing surgery Monday.
Williams was injured in the first quarter of his first career start during the 49ers' 29-3 loss Sunday night at Seattle. The third-year pro earned the job as the replacement for the departed Isaac Sopoaga with a strong offseason and training camp.
Coach Jim Harbaugh said: "Looks like he's going to be out for the year. Disappointing, and he'll have surgery today."
Veteran Glenn Dorsey will take over the position.
Rookie free safety Eric Reid was undergoing tests following his concussion, but Harbaugh said he wasn't experiencing symptoms Monday. Tight end Vernon Davis was having his injured hamstring examined.
AP NFL website: www.pro32.ap.org