Rangers manager Ally McCoist denies exploiting a Scottish FA (SFA) loophole by contesting Lee McCulloch's red card.
The midfielder was sent off for violent conduct in an incident with St Mirren's Graham Carey on Saturday.
With the SFA's fast-track tribunal unlikely to be convened before the new year, McCulloch will be available for Wednesday's Old Firm derby with Celtic.
"My initial reaction was that it was harsh and I still feel that," explained McCoist.
"We were in yesterday and myself, Kenny McDowall and Ian Durrant looked at it a few times.
"That's why we are exercising our right to appeal it."
When put to McCoist that he could be seen to be "pulling a fast one", he said: "I don't agree with that.
"That's not true. I still think Lee's sending-off was harsh."
Rangers will be without Dorin Goian for the clash at Celtic Park after the Romanian defender was also sent off at St Mirren, for two yellow cards.
Dropped points against St Johnstone, Kilmarnock and St Mirren has seen Rangers' lead at the top of the Scottish Premier League reduced to one point, with Celtic winning eight in a row.
However, McCoist insists confidence is high in the visitors' squad.
"We will approach it in a positive manner, we'll always do that," he explained.
"We believe we can win the game and we have an opportunity to go four points clear.
"Of course it was a disappointing result against St Mirren, there is no doubt about that.
"But it is really important that we bounce back and there is no better place to do it."
Having lost two players to red cards on Saturday, McCoist is anxious to keep a full complement on the pitch at Ibrox.
"Discipline is vitally important in all games," he added.
"We believe that the sending off effectively cost us the game against a good St Mirren side on Saturday.
"So it's important to show discipline and keep your players on the park.
"I know this game will be shown all over the world, so it's even more important."