Mostert isn't in line to play in Saturday's preseason game at Tampa Bay.
Mostert and Chase Edmonds will be joined on the sidelines by quarterback Tua Tagovailoa and wide receivers Tyreek Hill and Jaylen Waddle. In place of Mostert and Edmonds, the Dolphins backfield will be occupied by Sony Michel, Myles Gaskin, Salvon Ahmed, Gerrid Doaks and ZaQuandre White on Saturday.