Head coach Kyle Shanahan told reporters Friday that Williams (ankle) is "trying to get back" and that his recovery has been "a lot slower than anticipated," Nick Wagoner of ESPN.com reports.
The All-Pro offensive lineman was sidelined for the 49ers' Week 15 loss to the Rams on Thursday night due to an ankle injury, but Shanahan's comments Friday indicate he may return at some point this season. Williams has now missed each of San Francisco's last four games, and Jaylon Moore is likely to continue protecting Brock Purdy's blindside until Williams has recovered.