It appears the test reinforced McKinnon’s initial feeling. Adam Schefter of ESPN reports that the test showed McKinnon suffered a muscle strain.
There’s no word on any time that McKinnon might miss, but the 49ers will likely be on the cautious side with a player that’s set to fill a major role for them during the 2018 season.
McKinnon’s injury came a few days after the 49ers saw six players leave their preseason opener with injuries. All are likely to miss some time, but coach Kyle Shanahan said all are expected back for the start of the season.