Harry Redknapp has hit out at Ben Thatcher for his 'horror' challenge on Portmouth midfielder Pedro Mendes.
The Man City defender seemed to hit Mendes with a forearm at the start of the second half, leaving the Portuguese midfielder needing hospital treatment.
"Off the field, you could not meet a nicer boy," said Redknapp of Thatcher. "Unfortunately, on the pitch he is capable of doing things like that.
"It was an horrendous challenge and totally out of order."
Mendes needed oxygen treatment on the side of the pitch after skidding into advertising hoardings.
"As soon as I saw Thatcher running into the corner, I knew what was coming. I would have bet my life on it," Redknapp added.
"How can that not be a sending off? What do you have to do, kill someone?"
"He suffered some kind of fit or seizure. We had to give him oxygen and he wasn't in a great way when he left the stadium, but we will see how he is tomorrow."
Thatcher was only booked by referee Dermot Gallagher for the challenge but could be hit by a Football Association charge when video evidence is reviewed.
Pompey midfielder Matt Taylor was incensed by the tackle.
"How can that not be a sending-off? What do you have to do, kill someone?" he said.
"The FA have to look at it. It is there for all to see. I like Ben as a guy but that was wrong."
City boss Stuart Pearce said he had not seen replays of the offence, but agreed that Thatcher had fouled his opponent.
"I saw Ben running into the corner at 110 miles per hour," said Pearce.
"I want the players to play at a high tempo near the ball and it looks like the tackle was a bit mis-timed."
Pearce also said Thatcher had inquired about Mendes' health after the game.