The San Francisco 49ers have lost Jerick McKinnon to a torn right ACL, which he suffered while making a cut on the last play of practice Saturday.

McKinnon missed most of the preseason with a calf strain suffered in practice Aug. 12. He was working his way up to speed and was expected to be ready for the September 9 opener against the Minnesota Vikings.

The 49ers signed McKinnon to a four-year, $30 million deal in the offseason.

With McKinnon injured, San Francisco is left with Matt Breida, Alfred Morris and Raheem Mostert at running back.