Forest boss Philippe Montanier, who insisted he was not concerned about his position despite chants form the travelling fans, described the sending-off as "incredible".
Montanier said: "If you receive a yellow card every time you push the ball [at an opponent], you would finish with 10 yellow cards against 12 yellow cards.
"It's incredible because even the referee didn't see anything, it was just the fourth [official] exaggerated a lot.
"For me, it is incredible, but I prefer not to comment on this decision. You saw what happened. But you can't change that."