It's the latest example of the outcry that has followed the surprise recommendation announced on February 12.
The IOC recommendation, which came as a surprise to many states that tend to excel in wrestling, could lead to the sport's exclusion from the 2020 Olympics.
Daghestani gold medalist Sagid Murtazaliev announced his protest in an open letter to the IOC, according to sports.ru and Interfax reports, quoting from a Makhachkala press conference.
Murtazaliev bested the competition in the heavyweight class in the freestyle wrestling event in the Sydney Olympics more than 12 years ago. He is also a legislator for the ruling United Russia party in Russia's republic of Daghestan.
His challenge follows angry responses to the snub from Iran, Russia, and the United States, as well as smaller players like Tajikistan, Bulgaria, and Georgia, to name a few.
Wrestling's inclusion dates back to the Olympic Games of ancient Greece, adding fuel to their ire.
Murtazaliev's declaration comes as U.S. and Iranian officials at tense nuclear talks in the Kazakh capital "found rare common ground" on the topic of wrestling's rightful place in the Olympics, according to Reuters.
A U.S. official was quoted as saying that during the multiparty talks "we did note Iran's success in the recent wrestling World Cup and our shared view that wrestling should continue to be an Olympic sport."
But wrestling, one of Iran's most popular sports, has proven a rare arena in which the two countries have friendly relations.
U.S. wrestlers visited Tehran last week to compete in the World Cup, where 2012 Olympic gold medalist Jordan Burroughs was cheered on wildly by Iranian fans at the capital's Azadi Stadium.
"Iran has amazing fans!" Burroughs tweeted, posting a picture of Iranian supporters eagerly reaching down over a barrier at the stadium to touch his hand.
Another U.S. official was later quoted as saying, "We and Iran agree completely that the Olympics should continue to have wrestling as a sport...so we will be working vigorously with them to make that come to pass."
The IOC's demotion means wrestling must compete against seven other sports for a place among the nearly 30 other sports that will be included in the Olympics, the world's biggest sporting spectacle.
Since the IOC's decision, the president of the International Wrestling Federation has stepped down.
And the president of Bulgaria's wrestling federation, Valentin Yordanov, has also sent back his Olympic gold medal from the 1996 Summer Games in Atlanta.
-- Andy Heil