49ers RB Jerick McKinnon suffers season-ending knee injury in practice

NFL coaches and general managers routinely say cut-down day, when hundreds of players lose their jobs across the league, is one of the grimmest on the calendar. And it was particularly brutal for the 49ers on Saturday. In the morning, not long before the 49ers officially pared their roster to 53 players, starting running back Jerick McKinnon, who was signed to a four-year, $30 million extension in March, suffered a torn ACL, a league source said. It was McKinnon's first full practice since he calf injury sidelined him for the final three preseason games in mid-August. Even before McKinnon's injury was confirmed by an MRI, head coach Kyle Shanahan feared he could be lost for the season.