NFL Network Insider Ian Rapoport reported Friday that the Niners are expected to place the running back on injured reserve, per sources informed of the move.
What isn't clear yet is whether it's season-ending IR or whether he'll be eligible to return. If San Francisco places McKinnon on IR before Saturday's cutdown deadline (4 p.m. ET) his season is over. If, however, they carry him on their final 53-man roster and then place him on IR, he'd be eligible to return after eight weeks, if healthy.
The 27-year-old suffered a torn ACL last year and missed the entire season. McKinnon looked poised for a return to a crowded backfield but recently suffered a setback to his surgically repaired knee. Rapoport noted that he might have a procedure to fix the issue.