Winters is day-to-day due to a neck issue, Lindsey Pallares of the 49ers' official site reports.
Winters appears to have hurt his neck in some manner during Thursday's Week 15 loss to the Rams. He logged six defensive snaps and 12 special-teams snaps in the loss, finishing with one tackle. Winters' nine percent defensive snap share was his lowest of the campaign, though it's not clear if that was due to the neck issue or more related to Dre Greenlaw (Achilles/knee) making his season debut. Winters had originally been deemed questionable to return early in the first quarter Thursday but re-entered the contest before the period ended.