McGuckin only informed his players of his decision following the Tyrone champions’ first round win over Mullahoran and Ballinderry’s Derry final win over Slaughtneil on Sunday.
McGuckin, who was part of the Ballinderry team that won the Andy Merrigan Cup in 2002, had also elected not to train the team ahead of the clash.
“The bottom line is Ronan had, unbeknownst to us, stated to the selection committee when he was going for the job that if it ever came to pass he wouldn’t be able to manage us against Ballinderry,” said three-time All-Ireland winner McGinley .
“The club people never told us (the players) because there was no need.
“We were a long way from an Ulster championship and it was a very long shot. We only found out about it after the game on Sunday.
” Ronan’s decision was more extensive than what I had thought or what I still think was possible.
“In all the talks he’s had with us, he’s been very effusive in his praise of us boys and with that a tight bond develops.
“With his removal, that comes as even a bigger shock and that’s how I feel right now – shocked and disappointed.
“He never hid the fact of being a Ballinderry man through and through and the fixture would have put him in a tight position.
“But it was a surprising and difficult meeting after the Mullahoran game.”
Errigal Ciaran’s assistant manager Tommy McDermott is expected to take charge of the team for the game in Omagh. However, McGinley intimated McGuckin may not be their manager should they defy the odds and beat Ballinderry.
Although it was suggested McGuckin would remain on were Errigal Ciaran to win, McGinley said: “That’s the way it was left although that’s a bridge that’s yet to be crossed.”