The Lightning lost some of its depth in the backend this morning with the start of free agency:
Korobov has been sent a qualifying offer from the Bolts, so he remains Lightning property in the NHL. He made his NHL debut during the 2013-14 season but played only 3 games, earning a single assist. His 71 games in the AHL with the Syracuse Crunch were looked at as somewhat regressive for his second year in North America. He posted 26 points with the Crunch (3 goals, 23 assists) but was a minus-12 on a rebuilding team.
Good luck to him back home.