Motherwell manager Ian Baraclough criticised the red card decision that helped push his side towards a 2-1 defeat by St Mirren.
Striker Scott McDonald was controversially sent off for violent conduct after a challenge with Thomas Reilly.
It was a result that means the Steelmen are consigned to a play-off, where they will face a two-legged tie against Rangers, Hibernian or Queen of the South in order to preserve their Scottish Premiership status.
"It's a poor, poor decision," Baraclough told BBC Scotland. "Having seen it again, over and over again, there's no malice in it, there's no intention to swing an arm back to make connection.
"The guy's gone down. Professionally he's gone and played the game in that respect, but he got straight up in the end and I think there's a comment made to one of their coaches of 'no he's not touched me' or 'he's not touched the player'. Whether it was from him or not I don't know.
"We'll be appealing that straight away. He's distraught in there, he's not that type of player, there's no history in it whatsoever. He's been hard done by and so have we in that respect."
Baraclough must now prepare his side for the play-offs, with a game to come against Partick Thistle first.
He said: "Everybody's got to be ready. Up for the battle, up for the task of now making sure we come through them play-offs.
"I've gone round individuals, what their qualities are. They can go and win games of football with their quality and we've got to show that as a group, as a collective, each bringing out their own individual quality to go and make sure the team performs and wins games of football."
St Mirren manager Gary Teale, whose side are already relegated, said the win may give a small glimpse of what an improving Buddies team can do in the Championship next season.
He said: "With the pressure off, hopefully the supporters are starting to see a wee taste of what could come next year.
"You see a lot of young boys coming in there and it's the way I'd like to go.
"Obviously you still need to have your experienced ones in there but it's good to have that youthful enthusiasm, that energy to take you from one end of the pitch to the other."