Dale Ferguson will miss Scotland's World Cup quarter-final against New Zealand at Headingley on Friday after losing his appeal against suspension.
The Huddersfield second rower was given a two-match ban by a review panel for a dangerous tackle on hooker Tui Samoa during Friday's 22-8 win over the United States.
He sought to over-turn the ban but the original verdict was upheld by an appeals panel hearing in Leeds on Tuesday.
"We're very disappointed but we accept the panel's decision and move on," said Scotland coach Steve McCormack. "It's unfortunate for Dale, who has probably been our stand-out player so far.
"It's a big loss but it gives an opportunity for someone else. We've a few players who can jump in there."
Meanwhile, there was better news for USA's Joel Luani, who has been cleared to play in Sunday's quarter-final against Australia after winning his appeal.
Luani was given a one-match ban after being found guilty of a dangerous throw during the same game but has succeeded in overturning the original verdict.