NFL Network Insider Ian Rapoport reported Sunday that Tagovailoa, who is dealing with rib and finger injuries, went through his pregame routine and couldn't go, per a source informed of the situation.
Jacoby Brissett will make his fourth start for the Dolphins.
Tagovailoa is expected to be active as the backup but would likely only play in an emergency situation.
The Dolphins were optimistic earlier this week that Tagovailoa could play through the discomfort in his injured finger, but following his pregame workout, the club decided its best chance to win was with Brissett instead of a very limited Tua.
It's the latest setback in the young QB's second season. He missed three starts earlier this season due to a rib injury. Tagovailoa has played well for stretches, showing good touch and accuracy. But he's also made some brutal errors, particularly in the red zone, that have led to game-swinging interceptions. In five starts, Tua has completed 65.6 percent of his passes for 1,049 yards, seven TDs and five INTs.
Not only will Tua's status for Sunday be affected, but with the short turnaround to a Thursday night game against Baltimore, Week 10 could also be in jeopardy.
Brissett will now attempt to help the Dolphins snap their seven-game losing streak against a similarly struggling 1-7 Houston squad.