USA centre Paul Emerick has lost his appeal against a five-week suspension for a dangerous tackle on England's Olly Barkley last weekend.
Emerick upended Barkley in England's 28-10 victory on Saturday
Emerick, 27, was cited and then banned after being seen to "spear" Barkley in the 28-10 World Cup defeat in Lens.
He appealed against the sanction but the three-man appeals committee upheld that judgement.
"The appeal committee was satisfied that the tackle in question was very dangerous," said a statement.
"In the circumstances, a five-week suspension was the correct sanction."
At the original disciplinary hearing, officials said there was a "deliberate tipping motion in the tackle with an element of force driving the opposing player downwards".
The offence carries a 10-week ban but mitigating factors were considered.
Emerick's good record, his good behaviour and that of his representatives from USA Rugby at the hearing, and the fact that he showed remorse in relation to the incident were all taken into account but his tournament is effectively over.
He would only be able to play again if the United States were to reach the final.