Sobotka played four seasons with the Blues from 2010-14 and had 29 goals and 101 points in 247 games. He became a restricted free-agent the summer following the 2013-14 season and was seeking a contract paying him $3 million per year.

The Blues balked, opting for arbitration, where Sobotka was awarded $2.725 million on a one-year contract. The forward instead signed a three-year deal with Avangard worth an estimated $4 million per season. He left knowing that in order to return to the NHL, he "owed" the Blues one year at the arbitratration-elected salary.

Sobotka's KHL contract had an out-clause that allowed him to leave after each of year. He made plans to return to the NHL for the 2016-17 season, but after the Blues counted on him to report to training camp in September, they learned that Sobotka re-worked his contract with Avangard after a downturn in the Russian economy and the out-clause was omitted. There was a buyout, but it was reportedly close to $3 million and Sobotka believed it was senseless to pay Avangard and essentially play the '16-17 season with the Blues for free.