Third-year nose tackle
San Francisco’s first-year starter was injured in the first half of Sunday’s 29-3 loss to the Seattle Seahawks.
Williams is undergoing surgery on his broken left ankle on Monday.
PHOTO GALLERY: 49ERS VS. SEAHAWKS
In the first half of Sunday night’s NFC West slugfest, Seattle right guard J.R. Sweezy rolled into Williams’ left leg, immediately knocking the 6-foot-1, 305-pound defensive lineman to the ground. Williams did not return to the game.
“It was an unfortunate play,” Jim Harbaugh said, declining to go any further into the subject of Sweezy's block.
The 49ers coach commended the play of Williams’ backup,
With Williams headed for Injured Reserve, the 49ers are down to five healthy defensive linemen.
In additioin to Dorsey who will start at nose tackle this week, the 49ers have
Harbaugh said the 49ers are evaluating replacement options for Williams’ roster spot.
Elsewhere on the injury front, Harbaugh said rookie
Reid will have to pass the NFL’s concussion protocol in order to return to the field this Sunday against the visiting Indianapolis Colts.
As for two other injured players in the loss to Seattle, Harbaugh said he had no information to share on McDonald, who was helped off the field in the fourth quarter. Harbaugh added that tight end