The 49ers plan to place McCaffrey (knee) on injured reserve, Ian Rapoport of NFL Network reports.

EDGE Analysis

Coach Kyle Shanahan announced Monday that McCaffrey suffered a PCL injury in his knee, and he will be sidelined at least six weeks, Rapoport added. McCaffrey was injured in the first half of Sunday night's eventual loss to the Bills, and he's now going to miss the rest of the regular season. In addition, McCaffrey's backup, Jordan Mason, suffered a high-ankle sprain against Buffalo and also is heading to IR, knocking him out until at least Week 18. The development vaults Isaac Guerendo into the 49ers' RB1 spot atop the depth chart, making him a priority add in all fantasy leagues. Patrick Taylor currently is on the team's practice squad but likely will be promoted this week.