McDaniel told reporters on Wednesday that they reviewed film from last Saturday's defeat to the Green Bay Packers and questioned Tagovailoa on how he felt after a particular hit, sending him to see the doctors after some inconsistencies in the quarterback's behaviour caused concern.
The Dolphins are 8-7 for the season following the loss to the Packers, in which Tagovailoa threw three interceptions, and have now suffered four losses in a row, but have the head-to-head edge over the Patriots (7-8) in the race for the final playoff spot in the AFC. The Dolphins beat the Patriots at home in Week 1.
Despite the significance of the Dolphins' two remaining regular-season games, McDaniel made it clear that Tagovailoa's health holds more importance.
"This is a private time for him to focus on his health. This is a human being. His health is the first and only priority," he said.
The injury marks Tagovailoa's second diagnosed concussion this season and the third time he has been evaluated for a concussion this season.
Tagovailoa missed two games in October after a previous concussion, where he was hospitalised during a 27-15 Week 4 loss to the Cincinnati Bengals after being whipped around and flung to the ground by the Bengals' Josh Tupou, causing his head to snap back onto the turf.
The Dolphins were heavily criticised for having the quarterback on the field just four days after an incident in a 21-19 win over the Buffalo Bills, where he was pushed to the ground by linebacker Matt Milano, causing Tagovailoa's helmet to slam into the turf. He managed to get back on his feet quickly, but after shaking his head and looking woozy, he appeared to lose his balance as he stumbled back to the ground.
After heading to the locker room, the Dolphins said he was questionable to return, but he missed just three snaps and returned for the start of the third quarter – which prompted the NFL and National Football League Players Association to conduct a joint review of how the decision was made to allow Tagovailoa to return.
McDaniel maintained the proper protocols were followed but the neurotrauma consultant who evaluated and cleared Tagovailoa was later fired by the NFLPA.
The NFLPA has initiated a joint review into the application of the concussion protocol for Tagovailoa surrounding this latest head injury.