After the 2013-2014 season ended, he became a restricted free agent. Sobotka decided not to resign with the Blues and instead he was signed to a three-year contract by Avangard Omsk of the Kontinental Hockey League (KHL). When the possibility of Sobotka playing in the KHL became clear, the Blues filed for salary arbitration in the NHL. On July 21, 2014, Sobotka received a one-year, $2.725 million award from an arbitrator. The result of the arbitration award is if Sobotka decides to return to the NHL at a later date, the Blues will retain his rights for a year at the amount that was awarded by the arbitrator. At the end of that year, Sobotka will become an unrestricted free agent in the NHL.