England prop Joe Marler has been cited for allegedly striking an opponent in his side's win over Wales on Saturday.
The charge relates to an incident in the 15th minute of the first half of the Six Nations match at Twickenham, which was won 25-21 by England.
Marler is alleged to have broken Law 10.4 (a), which applies to punching or striking and says "a player must not strike an opponent with the fist or arm, including the elbow, shoulder, head or knee(s)".
In an eventful first half for Marler, the Harlequins loosehead appeared to land a forearm in the face of Wales front row Rob Evans while trying to help team-mate Dan Cole ground the ball over the Welsh try-line.
The offence carries an entry-point sanction of two weeks and he will appear before a Six Nations disciplinary hearing this week with the outcome almost certain to rule him out of Saturday's Grand Slam match against France.
The citing of Marler follows that of Wales' Tomas Francis and England's James Haskell from the same game, charges which were confirmed on Sunday night.
An incident of alleged verbal abuse involving Marler, for which he apologised to Welsh forward Samson Lee on Sunday, is still being investigated.
England head coach Eddie Jones told Sky Sports: "Joe handled it well. He obviously said the wrong thing, and immediately apologised at half-time, which shows how serious he was about apologising. We have just got to get on with it now."
England will bid for a Grand Slam in France on Saturday and, if Marler has to miss the match, Jones is confident the squad has the depth to cope.
"We have a great situation," he said. "Mako Vunipola could step in and start. Him and Joe have been battling all season for that spot, and Matt Mullan can come in on the bench."
Francis appeared to make contact with the eye of England tighthead Cole late in the game and match citing commissioner John Cole has cited him under Law 10.4 (m) - acts contrary to good sportsmanship.
If Francis is found guilty at the disciplinary hearing, which will be held this week, be could be looking at a lengthy ban - possibly 12 weeks or more.
Haskell, meanwhile, received a citing commissioner warning for a dangerous 'neck roll' tackle in the 16th minute of the contest.