Mikhnov played two games for the Oilers this season and appeared in 27 others with the Wilkes-Barre/Scranton Penguins of the American Hockey League.
The former first-round draft pick will play for Lokomotiv Yaroslavl in the Russian Super League. The 24-year-old spent the past nine seasons playing in Russia before coming to North America.
He was held scoreless in his two NHL appearances and had six goals and 18 points with Wilkes-Barre.
The Oilers support Mikhnov's move, which makes his case much different than the two other players who bolted for Russia earlier this year.
Alexei Kaigorodov was suspended by the Ottawa Senators when he refused an AHL demotion and returned home in Novemeber. He was subsequently dealt to Phoenix for Mike Comrie.
The Coyotes also suspended Russian forward Enver Lisin when he failed to report to their AHL team.