Inverness defender Chris Hogg has lost his appeal against the red card he received in the defeat by Motherwell.
Hogg was dismissed after his tackle on Jamie Murphy in Saturday's match was deemed as having denied an opponent a clear goalscoring opportunity.
And the Scottish FA's fast-track tribunal has upheld referee Crawford Allan's decision.
"I'm absolutely astonished at the decision," said Inverness assistant manager Maurice Malpas.
"I'm astonished that they believed that the referee was correct, that Jamie Murphy had complete control of the ball and was going to score.
"We thought we had a very good case but the compliance officer and the panel were of the same mind with the referee.
"We're upset at the consistency of the referees in terms of the decision here and the decision at Tynecastle on Saturday.
"That's for the SFA to try to solve. That's for the SFA to try and explain.
"Our situation is that Chris Hogg misses Saturday now, an important player in our team who has been out for a long time, who'll be twiddling his thumbs on Saturday at the game."