Romero had banged heads with Brentford's Bryan Mbeumo in an incident that stopped play before he then headed the 11th-minute opening goal.

Postecoglou took him off as soon as a VAR investigation into the goal was complete, with the player obviously unhappy with being substituted.

"He got a head knock and obviously it's pretty clear. The medical team were kind of just monitoring him as he was kind of progressing from there," the Australian told reporters.

"Then he scored with his head and they were pretty sure that we needed to, for his own benefit, get him off and what we know about head injuries for me it's not even an issue, we always err on the side of caution.

"The player's not the one you listen to in that situation because he doesn't know what's going on either. It's pretty clear what we had to do."

Postecoglou said a mistake was made in filling out the wrong slip for the substitution, costing him a regular change of player.

Asked whether Romero might be available for Tottenham's next league game at home to Manchester United on Saturday, given the protocols on concussion, Postecoglou said he did not know.

"That's where people like me should just shut up and listen to the doctors so that's what I'm going to do," he said.

"I think we've gone beyond the stage of managers or players trying to get funny about these things.

"It's clear there are protocols, they're there for a reason and the welfare of the player is paramount, so that decision will be made by people who know about the subject far more than I do."