The Ulster flanker was dismissed for what was deemed a high tackle on Scarlets' Aled Davis
World Rugby's new laws on tackling will take some getting used to for all parties involved.
Introducing measures such as these midway through the northern hemisphere season was bound to cause some difficulties. Referees, coaches and above all, players, are still coming to terms with what constitutes a high tackle.
Speaking on Tuesday's Off The Ball, Dr. Barry O'Driscoll, a former Ireland international and former IRB chief medical adviser, gave his thoughts on the rules and pointed out that there will be some teething problems in implementing the new rules.
Fans were given a taste of some of the new rules coming into effect last night during Ulster's clash with Scarlets in the Guinness PRO12.
Just past the hour mark, the Irish province held a slender lead over their Welsh counterparts but were camped deep in their own half. Aled Davis broke away from the back of a maul and darted for the line, crouching slightly as he braced for contact.
On both sides, both Andrew Trimble and Sean Reidy came in to halt his progress. The pair held him up from the line, forcing referee Marius Mitrea went to the TMO.
Upon reviewing the replay, the officials judged the tackle to be high and sent Reidy to the sin bin, while at the same time awarding a penalty try.
Scarlets’ Jake Ball also suffered the same fate minutes later for a challenge on Ulster's Clive Ross.
Discussion is likely to continue over the weekend with a number of Champions Cup matches set to take place and into the coming weeks as players continue to adapt to the new rules of the game regarding high tackles.