The Dolphins placed Willis (core) on injured reserve Tuesday.
As anticipated, Miami elected to move Willis to IR after an MRI on Monday revealed that his lingering groin issue and developed into a more concerning core-muscle injury that would require some time off. Willis is expected to treat the injury with a regimen of rest and rehab, leaving the Dolphins optimistic that he'll be able to return to action before the end of the season. With his move to IR keeping him sidelined for at least the next four games, however, the Dolphins will move forward with second-year player Kyle McCord as their new starting quarterback in the interim.