Pyeongchang, South Korea (CNN) Russian curler Aleksandr Krushelnitckii is suspected of failing a doping test at the PyeongChang Olympic Games.

Krushelnitckii, who won bronze in the mixed doubles event at this year's Olympics, is awaiting the results of a so-called "B sample," which could be known as early as this evening local time in South Korea.

The Court of Arbitration for Sport (CAS) said in a statement Monday it has initiated the process of reviewing Krushelnitckii's case after a request by the International Olympic Committee (IOC). A hearing date has not been set, the statement said.

Earlier in the day, Konstantin Vybornov, a spokesman for the Olympic Athletes from Russia, declined to name Krushelnitckii but said an official comment would be made after the results of the second test.

Aleksandr Krushelnitckii of Olympic Athletes from Russia looks on during the Curling Mixed Doubles bronze medal game.

More than 160 Russian athletes who could prove they were clean from doping are competing in a Olympic Athletes from Russia (OAR) team after the nation was banned from the Games because of state-sponsored doping leading up to and including the 2014 Sochi Winter Games.

Japanese speed skater Kei Saito was sent home from the Olympic village last week after becoming the first athlete at the 2018 Olympic Games to return a positive drugs test. The Court of Arbitration for Sport (CAS) said Saito voluntarily accepted his provisional suspension after an out-of-competition test turned up signs of a masking agent.

IOC reaction

In a statement posted to Twitter Sunday, the IOC declined to comment on individual cases, but said it took note of the statement by the OAR spokesman.

The IOC said it "cannot communicate on individual cases while the procedure is still ongoing," because "doping testing and sanctioning at the Olympic Winter Games PyeongChang 2018 is independent from the IOC."

IOC response to OAR statement regarding a notification of an Adverse Analytical Finding pic.twitter.com/pF9LHJhLZg — IOC MEDIA (@iocmedia) February 18, 2018

IOC spokesman Mark Adams said at a daily press briefing Monday it would be "extremely disappointing for us if a case is proven."

"On the other hand, what is does show is we have a system which is effective and protects the rights of the clean athletes," he added.

Several media outlets in Russia are reporting the positive test is for meldonium, the same substance for which tennis star Maria Sharapova was banned.

Athlete reactions

The use of meldonium, which was added to the list of banned substances by the World Anti-Doping Agency from 2016, is widespread in Russia and eastern Europe, where it is often taken as a heart drug.

Meldonium was added to the prohibited list "because of evidence of its use by athletes with the intention of enhancing performance," according to WADA's website.

American curler Matt Hamilton told reporters whatever the circumstances, Krushelnitckii, should be stripped of his medal.

"I feel for the guy if he didn't take it knowingly but you're responsible for what goes into your body so I think they would have to strip him of his medal."

Matt Hamilton, in response to Aleksandr Krushelnitckii testing positive for meldonium, said the drug does have advantages to it.

Hamilton said while the benefits of using meldonium isn't immediately apparent in curling, it does have its advantages.

"Curling's a finesse game, but there's a lot of strength and endurance and when you have more strength and endurance, you have a larger window to throw your shot into.

"So there is advantages to it. It's not quite as apparent as something like a cross-country skier or maybe a distance runner or even a weightlifter, but there is absolutely strength and conditioning and fitness in curling and it will give you a little bit of an edge even if it's not on every shot in every end."

Photos: Winter Olympics: Monday, February 19 Gigi Marvin, top right, celebrates with her American teammates after scoring the opening goal against Finland. Team USA won 5-0 to advance to the final. Hide Caption 1 of 18 Photos: Winter Olympics: Monday, February 19 German ski jumper Stephan Leyhe competes in the team event. Germany won the silver. Norway finished in first. Hide Caption 2 of 18 Photos: Winter Olympics: Monday, February 19 German bobsledders Francesco Friedrich and Thorsten Margis, right, react as they watch the final run by Canada's Justin Kripps and Alexander Kopacz. The two teams will share the gold after finishing with the exact time over four runs. Hide Caption 3 of 18 Photos: Winter Olympics: Monday, February 19 Team Canada celebrates after scoring a semifinal goal against the Olympic Athletes from Russia. Canada won 5-0 and will be in the gold-medal game once again. Hide Caption 4 of 18 Photos: Winter Olympics: Monday, February 19 A Japan supporter watches the ski jumping competition. Hide Caption 5 of 18 Photos: Winter Olympics: Monday, February 19 Colombian speedskater Pedro Causil, right, competes in the 500 meters. Hide Caption 6 of 18 Photos: Winter Olympics: Monday, February 19 American Becca Hamilton delivers a stone during a round-robin curling match. Hide Caption 7 of 18 Photos: Winter Olympics: Monday, February 19 Austrian ski jumper Gregor Schlierenzauer lands during the team event. Hide Caption 8 of 18 Photos: Winter Olympics: Monday, February 19 Canadian ice dancers Tessa Virtue and Scott Moir broke their own world-record score to take the lead after day one of the Olympic ice dancing competition. The duo won gold in 2010 and silver in 2014. Hide Caption 9 of 18 Photos: Winter Olympics: Monday, February 19 US skier Lindsey Vonn makes a face after completing a downhill training run. Hide Caption 10 of 18 Photos: Winter Olympics: Monday, February 19 Americans Maia Shibutani and Alex Shibutani are in fourth place after Monday's short dance. Hide Caption 11 of 18 Photos: Winter Olympics: Monday, February 19 Japan's Chinami Yoshida throws a stone during a curling match against Canada. Hide Caption 12 of 18 Photos: Winter Olympics: Monday, February 19 Canadian snowboarder Brooke Voigt competes in the big-air event. Hide Caption 13 of 18 Photos: Winter Olympics: Monday, February 19 Finland's Ronja Savolainen, right, collides with American Meghan Duggan during their hockey semifinal. Hide Caption 14 of 18 Photos: Winter Olympics: Monday, February 19 British duo Penny Coomes and Nicholas Buckland compete in the ice dancing. Hide Caption 15 of 18 Photos: Winter Olympics: Monday, February 19 Czech snowboarder Katerina Vojackova crashes during the big-air competition. Hide Caption 16 of 18 Photos: Winter Olympics: Monday, February 19 South Korea's Yura Min and Alexander Gamelin skate together in the ice dancing. Hide Caption 17 of 18 Photos: Winter Olympics: Monday, February 19 Slovakia's Klaudia Medlova competes in the big-air event. Hide Caption 18 of 18

Four-time Olympian John Shuster, who's on the same American team as Hamilton, said the doping was unfortunate.

"I've played in the same mixed doubles tournaments as that team and they're good people."

He said it was hard to see stories like this happen.

"You'd never know if it's on purpose or an accident, but that's been banned for a year and a half, and I can't imagine it's something that happened on purpose, so it's just unfortunate."

Hamilton said he felt for the other Russian athletes and how this scandal may affect them.

"I feel mostly bad for Russia because they got banned from this one and if some of their athletes are still getting caught positive, it's sad for them because who knows what the ramifications are going to be.

Flag

The news of a doping case in the OAR team could mean the athletes won't be able to march in their national uniform and with the Russian flag at the closing ceremony.

Although they competed under the OAR flag, the IOC had said beforehand the Russian athletes may have been able to march in their own national colors at the closing ceremony if they stuck to its strict code of conduct on neutrality.