Korobov, 6-foot-3, 230 pounds, played in 82 games with Dynamo Minsk of the Kontinential Hockey League during three seasons, recording two goals and 20 points with 46 penalty minutes.
Korobov played in a career-high 39 games last season, scoring one goal and establishing career highs for assists (10) and points (11).
Korobov, 23, was not chosen in the NHL Draft.
The Tampa Bay Times reports restricted free agent goalie Jaroslav Janus will play in Europe this season. He has not yet signed with a team.
Janus, 22, was 23-8-2 with a 2.36 goals-against average and .914 save percentage in 34 games last season for Norfolk in the American Hockey League.
Assistant general manager Julien BriseBois told the newspaper the Lightning are still interested in working with Janus, a 2009 sixth-round pick.