Harris (ankle) was downgraded from questionable and will not play Sunday against the Dolphins.
The news means Sony Michel will step back into the starting lineup as the primary two-down back, with James White (foot) mixing in as a pass catcher and J.J. Taylor (quadriceps) operating as the spellback in both situations. Harris, who popped up on the injury report Thursday with an ankle injury after missing time the previous week with a back issue, will aim for a return in Week 16 against the Bills.