Billings is set to undergo surgery to address a pectoral injury he sustained Sunday at Arizona and is expected to be out for a prolonged period, Patrick Finley of the Chicago Sun-Times reports.

The severity of Billings' injury wasn't immediately clear when it forced him out of the Bears' contest in Week 10, but it's now clear that he's dealing with a serious issue. In his stead, Chris Williams could move into a starting role on the defensive line.