Williams (back) isn't participating in Wednesday's practice, Lindsey Thiry of ESPN.com reports.
Williams failed to take the field for Tuesday's walk-though session, so what the wideout is able to do during Thursday's practice should be telling with regard to his chances of suiting up for Saturday's wild-card game against the Jaguars. On Monday, head coach Brandon Staley noted that Williams, who sustained a back contusion in Week 18, is expected to practice at some point this week before the Chargers take on Jacksonville.