The terms of his arbitration contract will be enforced when Sobotka returns to the NHL.
"We are looking forward to having Vladimir in a Blues uniform when he returns to the NHL," said Blues GM Doug Armstrong. "We wish him the best of luck in the upcoming season."
Sobotka, 27, dressed in 61 games with the Blues last season, posting a career-high 33 points, including nine goals and 24 assists.
Overall, Sobotka has appeared in seven NHL seasons, including four with the Blues, accumulating 123 points (35 goals, 88 assists) and 282 penalty minutes in 381 career regular season games.
The Trebic, Czech Republic native was originally acquired by the Blues via trade with Boston on June 26, 2010.