The Rugby Football League are investigating comments by Hull KR coach Justin Morgan criticising referee Ben Thaler.
Morgan was angered by Thaler's "substandard" performance in Rovers' engage Super League defeat by Huddersfield on Monday and said he did not want the official to referee his side's games again.
Morgan claimed Huddersfield were allowed to get away with "blue murder" and said Thaler needs to return to a lower grade and "spend some time learning the rules".
"It is absolutely disgraceful every time we get him," Morgan added. "There is a very common denominator every time there is a poor game of rugby league and that is Mr Thaler."
Morgan could face disciplinary action if the RFL decide he has a case to answer.
