McKinnon underwent an MRI on his right knee after reportedly injuring it in practice, the team announced. However, a source told NFL Network Insider Ian Rapoport reported that McKinnon's injury "does not appear to be major."
The 5-foot-9, 205-pound McKinnon suffered the injury during practice and was observed grabbing the back of his right knee, according to Matt Maiocco of NBC Sports Bay Area. Maiocco added McKinnon watched the remainder of practice after being checked out by medical personnel.
McKinnon, who joined San Francisco on a four-year, $30 million deal in March, was projected to open the regular season atop the depth chart.