The team’s statement on the move said Griffin has a fractured coracoid bone in his left shoulder. It said no surgery is required at this time and that Griffin will be evaluated again in 3-4 weeks.
Per the NFL’s injured reserve rules, the earliest he could return is Week 10.
“It’s very unfortunate, Robert came in and has worked extremely hard to learn our offense and earn the respect of his teammates,” Browns coach Hue Jackson said in the statement. “This is a tough loss because everyone has seen how invested he has been in this team and his dedication to the work needed to improve his craft. We all know these are the realities of the NFL, injuries occur and you have to find ways to overcome them so they don’t impede your progress.
“Robert will do everything in his power to rehab and get healthy but Josh McCown is on this roster for a reason and we have great confidence in him. He is more than capable. His veteran presence has been an asset to our team throughout our process of preparing for the season. We look forward to him assuming the role of the starter and leading our offensive unit.”
Griffin said after Sunday’s game that he suffered a sprained shoulder on the hit by Mills but said he would be OK. He returned for the game’s final series.
McCown started eight games for the Browns last year. Rookie Cody Kessler becomes the backup with Griffin out. The Browns added rookie Kevin Hogan to their practice squad after Hogan was released by the Chiefs earlier this month.