He appears to have paid the price for a wretched opening to the campaign which has seen last season’s Championship’s play-off semi-finalists tumble to 10th in the table.
Carnegie have gone five league games without a victory but, more worryingly as they try to attract support following their name change from Leeds, have still yet to win at home this term.
Friday’s dire 19-19 Headingley draw against bottom-placed Plymouth Albion, a side that lost all seven of its previous Championship fixtures this term, saw the frustrated board act.
Given some players had already publicly questioned Mercer’s tactics - the 48-year-old only appointed a fortnight before the season - it was no surprise.
Forwards coach Tommy McGee is set to be in charge for this Friday’s B&I Cup game at Aberavon with Mercer leaving having delivered just two Championship wins back in September.