The defender was featuring in just his third game for Sheffield United when a knee-high challenge on Kaoru Mitoma left audiences stunned.
Holgate, who had only just signed from Southampton during the January window, flew into the Japan international and planted his studs right into his knee in horrifying scenes.
Referee Stuart Attwell initially gave a yellow card, but didn't need much time to correct himself once he looked at his VAR screen.
Reacting to the incident, talkSPORT pundit and Arsenal legend Perry Groves said: "100 per cent a red card. Mason Holgate, what is he doing?
"That's VAR at its best. What is he doing? He comes across with Mitoma running down the wing, and it's reckless but not out of control.
"He knows what he's doing, he does take a little bit of the ball first and with his right foot he goes right across.
"Mitoma does well, he knows the challenge is coming and that he can ride it, if he has a planted foot that's a broken leg."
A number of fans echoed his thoughts, with one X user writing: "That's one of the worst challenges I've ever seen from Mason Holgate. Deserves a big ban. Outrageous."
Another added: "Mason Holgate should be banned for 10 games. Minimum. That's criminal."
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The incident came in the 13th minute with the game scoreless, but Brighton quickly went on to take a 2-0 lead.