Bills coach Sean McDermott told reporters the veteran quarterback will be "limited" for Wednesday's practice, per NFL Network Insider Ian Rapoport.
McCarron is still dealing with a dash of shoulder soreness, but the quick return is promising after the passer was initially believed to have suffered a broken collarbone in last week's preseason tilt with the Browns.
McDermott also noted that running back LeSean McCoy is day-to-day with a groin injury, saying, per NFL Network's Tom Pelissero: "There's always a concern ... LeSean's a big part of what we do. I know he's going to maximize those treatment opportunities, and he's a pro."
A healthy McCoy is locked in at running back, but Sunday's regular-season dress rehearsal will all but decide Buffalo's choice at quarterback ahead of the team's Week 1 tilt with Baltimore.