The inspiration for the famous Will Smith "Concussion" movie didn't mince words when talking about the matter on Friday ... saying straight up the consequences for allowing the 26-year-old back on the field after yet another concussion could be dire.

Specifically, Omalu says if Tagovailoa were to sustain another significant blow to the brain -- he could become "permanently incapacitated."

"As the corporation placing him back to play," Omalu said, "knowing fully well ... that there is a significant and substantial risk that this individual could suffer subsequent catastrophic and permanent brain damage -- then why would you place him back to play?"

For now, Dolphins head coach Mike McDaniel says the decision is in Tagovailoa's hands ... but at the moment, a timeline for a decision is the furthest thing anyone in the building wants to talk about.

That said, Omalu told us if he had any sort of affiliation with Tagovailoa, he'd strongly urge the football player to give it up.

"If I were his brother, his father, his uncle, cousin, nephew, if I were a member of his family," Omalu said, "I would beg him to retire."

Omalu, of course, has suggested this to Tagovailoa before ... following his significant head injury against the Bengals back in 2022.