Gaines (core muscle/groin) has been placed on injured reserve by the Bills.
Coach Sean McDermott said Tuesday this was immediately determined to be a multiple-week injury, and the Bills decided they can't hold the roster spot for what will end up being much of a lost season for Gaines. Injuries continue to mar Gaines' career, as he's been in the league since 2014 and has only played more than 11 games once. If he heals quickly enough, he can shoot for an injury settlement with the Bills in order to look for work elsewhere.