The Facts: The 49ers placed Mitchell on injured reserve for the second time this season after the running back suffered an MCL sprain in his left knee last weekend against the New Orleans Saints.

Diehards Line: Mitchell's earlier stint on the injured reserve list started on September 13 after suffering the same injury to his right knee in Week 1. The 49ers activated the second-year running back off injured reserve on November 12, and Mitchell rushed for 183 yards, averaging 5.38 yards per carry in the three games since his return. Meanwhile, the 49ers will go with rookie Jordan Mason and Tyrion Davis-Price behind Christian McCaffrey vs. the Dolphins on Sunday. They did not elevate veteran Tevin Coleman from the practice squad.