Following up on the ongoing story. ... The San Francisco 49ers placed Elijah 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.

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.

"He's pretty disappointed," head coach Kyle Shanahan shared the day after the injury occurred. "Everyone knows how good Elijah's been, how hard he worked to get back from his last one, how good he's been playing since he came back, and to kind of be right back there, I know he was real down on it. It's unfortunate for him. He's just had some real bad luck."

The 49ers expect Mitchell to miss six to eight weeks, similar to the time he missed during his earlier injury. Shanahan hopes to get Mitchell back for the playoffs, assuming the team can make a deep run for the second consecutive season.

"Hopefully, we can do our job here so, when he comes back, we're still playing," Shanahan said.

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.