Motherwell fuming after McDonald red card
McDonald was given a straight red card for violent conduct after an alleged elbow on Thomas Reilly in the 90th minute of the contest.
The red card means the Australian will cop an automatic three-game ban, but Motherwell boss Ian Baraclough was seething and said they’d appeal the decision.
The defeat consigned Motherwell to 11th spot with one game to play and a promotion-relegation playoff with either Hibernian, Rangers or Queen of the South.
McDonald could miss all three matches if the red card decision is upheld.
"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."
McDonald is out of contract at the conclusion of the 2014-15 season, having joined Motherwell on a short-term deal in February.
The Sunday Express reported earlier this week that relegated Championship club Wigan were interested in McDonald’s services.