Errigal Ciaran manager Ronan McGuckin will not be involved in the Ulster Club Football quarter-final against his home club Ballinderry on 4 November.
McGuckin has requested a leave of absence from the role for the game because of his conflict of interest.
Errigal Ciaran captain Enda McGinley says he is "disappointed and completely surprised" by the decision of McGuckin to step aside for the last eight match.
Errigal hammered Mullahoran 4-15 to 1-7 in the preliminary round on Sunday.
After Sunday's match at Breffni Park, McGuckin told the Errigal Ciaran players that he would request two weeks off from the job.
McGuckin's assistant manager Tommy McDermott looks likely to take charge of the Tyrone champions for the clash with Ballinderry.
McGuckin's departure is understood to be a temporary move, his decision taken over a conflict of interests, with Errigal due to face his home club Ballinderry in the next round.
Team trainer Tommy McDermott is set to take on the management role as the Tyrone champions prepare to meet the Derry giants at Healy Park on November 4.
"As an Errigal Ciaran man, and as a player with this team, I'm disappointed at the course of action he has taken, but he has never hidden the fact that he's a Ballinderry man first and foremost, and that has led him to his decision," said McGinley.
"To be 100 per cent honest, I was completely surprised and taken aback by it, and haven't really got over that emotion still.
"I sort of knew there would be a clash coming down the line, you could nearly foresee it."