Defending champion Park Tae-Hwan of South Korea was reinstated in the men's 400m freestyle Saturday hours after his sensational disqualification from the Olympic heats.
South Korea appealed the disqualification, for a false start, and the appeal went to world governing body FINA's Jury of Appeal.
A FINA spokesman said the Jury of Appeal's decision was based on the recommendation of FINA's technical commission.
Park's appearance in the final would leave Canadian Ryan Cochrane, who grabbed the eighth and final spot, out in the cold.
That raised the prospect of a protest by Canada.