Jerick McKinnon’s first 49ers season is likely over before it started.
A week before squaring off against his former team in the season opener, San Francisco’s new $30 million running back suffered a torn ACL in his knee and is all-but assured to miss the entire 2018 season, according to an NFL Network report after McKinnon underwent an MRI on Saturday.
It happened during a short informal practice on Saturday as San Francisco cut the roster down to 53 players. McKinnon was working his way back from a calf strain suffered during practice Aug. 12 and was expected to make his 49ers debut on the road against the Minnesota Vikings.