Reading have appealed against Alex Pearce's dismissal during Saturday's 2-0 defeat by Sheffield Wednesday.
Defender Pearce was sent off after just nine minutes for bringing down Benik Afobe in the penalty area.
But Royals boss Nigel Adkins is convinced Pearce was not the last man and that Kaspars Gorkss was covering his fellow centre-half.
After the match Adkins said: "I'll do everything I can to appeal it.
"To be honest, if he gives the penalty then you can live with that. The issue is the red card because he shouldn't have sent him off.
"How he can send Pearce off when Kaspars makes a challenge as he goes to ground? I just can't understand it.
"But the fact is the referee's given it and it's a shame for the players and for Pearcey."
The club have 24 hours to submit evidence to the Football Association with a decision expected later this week.
If the appeal fails Pearce will miss next weekend's trip to QPR.