Krushelnitsky, who won Winter Olympic bronze with wife Anastasia Bryzgalova in the mixed doubles, is suspected of testing positive for meldonium.

Cas opened a case against the 25-year-old following a request from the International Olympic Committee (IOC).

A hearing date has not been set and a B sample result is expected on Monday.

More than 160 competitors are in the Olympic athletes from Russia (OAR) team as their country was banned from the Games over "systemic" doping at Sochi 2014, which they hosted.

Russian athletes who could prove they are clean could compete under the OAR banner, with the team comprising 168 competitors - the third biggest behind Canada and the United States.

"It's a huge embarrassment for the IOC, given it let OAR compete," said BBC commentator Steve Cram.

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