Russell won a world bronze in 2005 and was an Olympic medal prospect
USA boxer Gary Russell Jr has been forced to withdraw from the Beijing Olympics after collapsing while struggling to make his weight.
After a workout in a final attempt to make the 54kg limit, the 20-year-old was found unconscious in his room.
Russell's withdrawal comes 24 hours after British medal hope Frankie Gavin was also pulled out for health reasons.
Team USA coach Dan Campbell believes Russell did not follow instructions to increase his fluid intake.
The highly rated bantamweight is said to be feeling "depressed" after being removed from the American team ahead of the tournament, which starts on Saturday.
Russell was rehydrated by medical staff at the athletes' village and although checks showed his condition was not serious, he was ruled unfit to take part in Friday's mandatory weigh-in.
"It's been extremely hot and that probably played a part. When trying to make weight, these kids sometimes cut corners," said Campbell.
"We believe he did not increase his fluid intake the way we had told him to."