49ers RB McKinnon Out for Season With Torn ACL: Source

The 49ers will not have the services this season of Jerick McKinnon, the running back coach Kyle Shanahan picked in free agency because of his playmaking ability.McKinnon sustained a torn anterior-cruciate ligament, a season-ending knee injury, a league source told NBC Sports Bay Area. The injury occurred during a non-contact play on the final play of practice on Saturday.McKinnon was injured in his first practice back after missing three weeks with a calf injury. An MRI examination on Saturday afternoon confirmed the extent of the injury, the source said.Now, the 49ers will now open the season with Alfred Morris and Matt Breida as the team's top two running backs. The 49ers signed Morris two weeks ago after injuries to McKinnon and Breida, who sustained a separated shoulder during the 49ers' first preseason game. Breida has been cleared to practice and play.Special-teams ace Raheem Mostert is the only other running back on the 49ers' roster. The club will likely look to sign another running back upon placing McKinnon on injured reserve to open a spot on the 49ers' 53-man roster.The 49ers did not attempt to re-sign Carlos Hyde in free agency, as Shanahan preferred McKinnon's...