The club says the 28-year-old suffered laceration of the capsule of the right shoulder's joint. Jankūnas will need an operation and around four months of rehabilitation, traumatologist Rimtautas Gudas said.
Jankūnas suffered the first shoulder injury in Milan during an ULEB Euroleague Regular Season game against EA7 Emporio Armani Milan on December 7. He continued playing wearing a special splint but suffered another injury during a game against Brose Baskets Bamberg last week.
"Doctors said we can no longer take risks and an operation is needed. I regret that everything happened this way but nobody is protected from injuries. This season could have been special but I still believe in the team and my friends. I will now try to support them the best I can sitting on the bench," Jankūnas was quoted as saying in a statement.
Jankūnas will be replaced by Croatian Marko Popovič as the team captain until Jankūnas recuperates.