By Alek Arend The San Francisco 49ers suffered two significant losses in Week 1 on Sunday afternoon. The first was an actual loss to the Chicago Bears. The second was an injury to a 49ers running back. That player is Elijah Mitchell. Elijah Mitchell exited the Week 1 game with a knee injury. Unfortunately, it appears he’s going to be forced to miss more time. Mitchell will reportedly miss a “few weeks” with a knee injury. Although the severity of the injury isn’t currently known, there’s a belief it’s serious enough to sideline him for an extended period of time. “#49ers RB Eli Mitchell, who w…