Leinster last night expressed their "shock" after flanker Shane Jennings was hit with a 12-week ban for eye-gouging the London Irish lock Nick Kennedy.
The Heineken Cup champions confirmed they will launch an appeal and questioned how Jennings could have been found guilty when Kennedy gave evidence stating the contact had been accidental.
The England lock had reacted furiously at the time of the incident, accusing Jennings of poking him in the eye, but claimed after the match that he had over-reacted.
Leinster issued a statement last night which revealed the club were "extremely disappointed" with the ruling, which they said came about "even though there was clear evidence from the opposition player that the act was not intentional".
The statement continued: "The ERC disciplinary committee appears to have found that Shane Jennings was careless with his actions, which is a shock to us.
"Shane has an impeccable record and a strong leadership role within the squad as our vice-captain and we will be appealing this decision."
Jennings is currently banned for eight matches, starting with Saturday's Heineken Cup trip to Brive and including the back-to-back European encounters with the Scarlets.
The Jennings case is the first high-profile incident since the International Rugby Board vowed during the summer to clamp down on the "heinous" offence of eye-gouging and eradicate it from the sport.
The IRB launched a review of its disciplinary procedures and wrote to all judicial officials following a spate of notorious incidents, including Schalk Burger's clash with Lions winger Luke Fitzgerald in the second Test.
The Lions felt Burger got off lightly with an eight-week suspension when Munster flanker Alan Quinlan was banned for 12-weeks for a clash with Leinster's Leo Cullen in last season's Heineken Cup semi-final.
Bath flanker Andy Beattie was also banned yesterday for three weeks following his red card for stamping against Ulster last Friday night.