49ers’ Jerick McKinnon avoids serious injury

The 49ers have received good injury news on a key player: Running back Jerick McKinnon, who left practice Sunday after grabbing at the back of his right knee, only suffered a calf strain, the team said. McKinnon will be sidelined for the rest of the week and will be evaluated next week. McKinnon, who signed a four-year, $30 million contract in March, underwent an MRI exam after sustaining the non-contact injury. McKinnon was briefly examined by the medical staff and observed the rest of practice before leaving for his test. McKinnon's injury came two days after six players — four starters and two key backups — left a preseason-opening win against Dallas with injuries.