Mostert (ankle/knee) didn't practice Wednesday, Travis Wingfield of the Dolphins' official site reports.
Mostert was listed with the same pair of injuries last week and ended up taking 20 carries for 94 yards and two touchdowns in a 34-13 win over the Jets. He'll likely be able to play again this Sunday against the Commanders, though there's a chance he'll have to share some of the snaps at running back with De'Von Achane, who has been listed as a limited practice participant since injuring his knee in a Week 11 win over Las Vegas. Achane sat out the Week 12 victory over the Jets but isn't expected to require another long-term absence.