England and Exeter winger Jack Nowell has been charged by the Rugby Football Union for criticising a refereeing decision in a Twitter post.
The 30-year-old made the comments about referee Karl Dickson following team-mate Olly Woodburn's red card during Sunday's thumping by Leicester Tigers.
Nowell, who did not play in the Premiership game, called it "one of the worst decisions" he had ever seen.
He has been charged for conduct that prejudices the interests of the game.
Nowell tweeted his 61,000 followers: "I'm actually in shock, like shock shocked. What the hell is happening? That's one of the worst decisions I've ever seen. EVER."
Nowell later deleted the tweet.
He will face an independent disciplinary panel on Wednesday.
Woodburn was shown a yellow card in the first half of Exeter's record 62-19 defeat for a deliberate knock-on. The back then received a second yellow card after the break for diving on Chris Ashton while attempting to force the Leicester wing into touch.
Team-mates Luke Cowan-Dickie and Henry Slade also criticised the red card but did not mention the referee.
Exeter next face Bristol on Saturday in the first of their final two Premiership matches, before travelling to La Rochelle eight days later for their Heineken Champions Cup semi-final.
Source: BBC Rugby Union News