Number eight Billy Vunipola will miss England’s opening game of the World Cup with Argentina following his red card against Ireland.
He was shown a yellow card for a high challenge on Ireland’s Andrew Porter on Saturday which was upgraded to a red.
The 30-year-old has been banned for three games, but it can be reduced to two if he completes the World Rugby coaching programme on tackling school.
England’s final warm-up game is against Fiji this Saturday.
The World Cup in France starts on 8 September and England meet Argentina the following day.
England coach Steve Borthwick will have to use the Fiji game to look at alternatives as Vunipola is the only specialist number eight selected in his 33-player World Cup squad.
Borthwick will also be without captain Owen Farrell for England’s first two pool games after World Rugby successfully appealed against the decision to overturn his red card in the win over Wales on 12 August.
The decision against Vunipola means England have had a player sent off for a high tackle by rugby’s new ‘bunker’ review system in their past two warm-up games.
Farrell became the first, having initially been shown a yellow card following a high tackle on Taine Basham.
Scrum-half Danny Care says England have been working on their tackle technique every day as they look to improve their discipline.
The ‘bunker’ system was introduced during the Summer Nations Series to support referees in making correct decisions.