Mitchell missed all of training camp this summer with a calf injury and returned last Sunday to play in the regular-season opener against the Seattle Seahawks. He participated in 15 snaps and recorded one tackle.
The Dolphins will lean heavily on second-year defensive tackle Jordan Phillips to start opposite Ndamukong Suh. Phillips played well in Week 1, recording four tackles and a half-sack against Seattle in 49 snaps.
Miami (0-1) will travel to face the New England Patriots (1-0) on Sunday.