Kris Boyd insists Philippe Clement's Rangers job is on the line in the club's next two fixtures against Motherwell and Celtic.
The Hoops currently boast a 12-point lead over their arch-Glasgow rivals heading into the Old Firm derby on Thursday, January 2 next week.
And Boyd claims if that gap increases at the turn of the year, then the Belgian should be removed from his position.
He wrote in the Scottish Sun: "Philippe Clement has two games to save his job as Rangers boss.
"Or he should have — IF the club is still operating to the standards I grew up with.
"Clement said the Boxing Day defeat at St Mirren was 'unacceptable'.
"He was right — but so too is Rangers being 12 points behind Celtic after 17 games.
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"If that gap grows to 15, or worse, this week then it has to be the end for Clement’s reign as boss.
"One TV camera panned to new Ibrox chief executive Patrick Stewart in the closing seconds at Paisley.
"We will soon find out what his remit is at Gers. And whether the club is serious about challenging Celts.
"Is Stewart simply there to balance the books, and be happy with the team finishing second to get a shot at the Champions League qualifiers?
"Or do Rangers still have ambitions to mount a serious challenge to Celtic?
"Clement will plead for patience, and repeat the same stuff about this being a huge rebuild and a young squad.
"But at half-time at St Mirren, he took off his most expensive summer signing in Nedim Bajrami and Connor Barron, who was his blue-eyed boy at the start of the season.
"They were hooked and replaced by two players he inherited 14 months ago.
"In fact, Gers finished the game with only THREE players signed by Clement.
"This is an expensively- assembled squad and nobody can tell me this team has progressed under him.
"There can be no excuse for falling that far behind Celtic so early in the season.
"Michael Beale and Gio van Bronckhorst both lost their jobs when the gap was smaller.
"St Mirren was huge for Clement and his players. If they had matched Celtic between then and January 2, they would have had the chance to cut the gap to six.
"Instead, Celts have now extended their lead to 12 points and, hand on heart, I’m not surprised.
"I’ve said it since the start of the season — there is something not right with Rangers on the football side.
"For me, Clement doesn’t completely trust all of his players and vice versa."
