Portadown have confirmed that they have launched an appeal to overturn the red card handed out to defender Chris Casement at Shamrock Park on Saturday.
Casement was sent-off in the 89th minute of his side's 1-1 league draw with Dungannon Swifts for allegedly head-butting Terry Fitzpatrick.
As it stands, the player is set to miss Saturday's Irish Cup semi-final against Ballymena United at the Oval.
The Ports are using video evidence to support their case.
Casement's team-mate Robert Garrett will miss this weekend's last-four clash because of an automatic suspension after being dismissed for a stamp on Swifts player Jamie Glackin.
The angry aftermath featured exchanges between the two sets of players, Casement being sent-off by referee Keith Kennedy because of what a referee's assistant deemed a head-butt on Fitzpatrick.
Fitzpatrick has agreed to support the former Linfield defender's case by submitting a letter to say that he was not the victim of a head-butt.
To add to the Ports' woes, midfielder Tim Mouncey was forced to limp out of Saturday's Premiership derby with a knee problem.
Portadown beat Ballymena in a penalty shoot-out the last time the two sides met in an Irish Cup semi-final in April 2010.