mouser
Business of Hockey
He's not getting loaned. If he chose to go to the KHL it's his choice not the Sabres. As is the decision to come back. He would determine when or even if it happens. In theory he could just stay there. As per dotcommunism's previous post, as long as the Sabres qualify him every year they own his rights until 2021.
Minor detail: the team doesn't have to qualify him every year. After the first QO they hold his RFA rights until he's eligible to become a UFA.