49ers head coach Kyle Shanahan said Monday that Williams (ankle) is out for the season, Lindsey Pallares of the 49ers' official site reports.
Williams has been sidelined since Week 12 with an ankle injury, and he'll remain sidelined for the final two games of the season. The star left tackle's recovery has been slower than expected according to earlier reports from Shanahan, and the team's elimination from the playoffs likely meant they weren't going to rush him back. Jaylon Moore is set to finish out the season in place of Williams after already filling in for him the last four games.