Lehtonen signed a four-year contract with SKA St. Petersburg of the KHL on Sunday, Sportsnet's Chris Johnston reports.
Lehtonen was placed on unconditional waivers by the Blue Jackets for the purpose of terminating his contract Tuesday.
Columbus placed Lehtonen on waivers Sunday, according to CBS Sports.
Lehtonen (lower body) returned to practice Saturday, Aaron Portzline of The Athletic reports.
Lehtonen is considered day-to-day with a lower-body issue, Blue Jackets team reporter Jeff Svoboda reports.