Down player Anton McArdle has lost his appeal against a six-month ban imposed for playing 10 minutes as a substitute for an Under-21 team while suspended.
The initial decision of Down's Competitions Control Committee has been upheld by the GAA's Ulster Council.
McArdle played for Burren against St Mary's in an U21 Championship game after being sent-off in the Ulster SFC final defeat by Crossmaglen.
McArdle had argued that he had been incorrectly advised by his club.
The rule breach, playing while suspended, carries an automatic ban of six months, barring the Jordanstown student from gaelic games until early summer.
McArdle brought his case to the Ulster Council on 19 January and was informed the following day that his appeal had failed.
McArdle's absence for the National League Division One series is a major blow for the Mourne county.
He is also ruled out of UUJ's Sigerson Cup campaign.