Skipper Jim Magilton says referee Lee Mason told him he was going to show Sito a yellow card and not a red after Kevin Lisbie had gone to ground during Sunday's East Anglian derby with Norwich City. Magilton felt Mason's decision to send the full-back off ruined the match.
The Northern Irishman said: "The referee saw it from the same angle as I did and there was no way it looked like a professional foul to me.
"It was a tangle of legs and when I approached the referee after he had blown he told me he was going to show a yellow card. But half a minute later, after all the jostling, he took out a red card.
"I don't know what made him change his mind, but my opinion of referees at the moment is not very high. Sito is the nicest lad on the planet and it was never a sending-off offence. It ruined the game."
Town have launched an appeal against the red card. If they are unsuccessful Sito faces a two-match ban, Saturday's dismissal being his second this season.