England could be forced to do without Courtney Lawes for some or even all of their World Cup campaign after the Northampton lock was cited for a clash with Mario Ledesma during Saturday's unconvincing win over Argentina.
Lawes is accused over striking the veteran Pumas hooker with his knee in the 13-9 victory in Dunedin.
The 22-year-old will now appear before a disciplinary hearing in Auckland tomorrow morning at 3am BST.
Lawes, who won his 11th cap at the weekend having made his international debut against Australia 15 months ago, is the first player to be cited at this year's global gathering.
Sanctions for the law 10.4(a) offence of "punching or striking (with the knee)" carries a sentence of between three weeks and 12 months, meaning that a guilty verdict could seriously endanger his hopes of playing a further part in his first World Cup.
"We will provide any information required and attend as requested," was England manager Martin Johnson's brief response before stating that no further comment would be made until after the hearing.
The citing is an un-needed disruption to England's preparations for the game against Georgia next Saturday, although Johnson may have been tempted to rotate his squad and play one or both of Simon Shaw and Tom Palmer in the second row regardless of the situation involving Lawes.
England have brought their own QC, Richard Smith, to New Zealand to help deal with any legal issues such as disciplinary hearings and he and the England management will likely argue that any contact between Lawes' knee and Ledesma's head was unintentional.
Ledesma lay motionless for a short time after Lawes hammered him into touch as he attempted to score in the right-hand corner at the end of the first half. The 36-year-old was able to carry on playing after treatment but there was no such luck for Pumas centre Gonzalo Tiesi, a second victim of Lawes' tough-tackling approach.
Tiesi has been ruled out the tournament after a huge, and legal, hit from Lawes when Argentina were on the front foot at the Otago Stadium.