San Francisco 49ers running back Christian McCaffrey has been sidelined once again after suffering a posterior cruciate ligament (PCL) injury during the team’s 35-10 loss to the Buffalo Bills on Sunday, according to ESPN. Head coach Kyle Shanahan confirmed on Monday that McCaffrey would be placed on injured reserve, with a recovery timeline of six weeks, putting the remainder of his season in jeopardy. McCaffrey’s injury came during the second quarter of Sunday’s game when he pulled up abruptly on a run. The injury appeared to be non-contact, and McCaffrey was quickly escorted to the blue medical tent before walking…