According to Igor Eronko of R-Sport, Panarin has already decided on the Hawks, with an agreement that he’ll return to the KHL if he doesn’t make the roster.
His contract with SKA expires April 30th, I don’t think he can officially sign until then.
Plus, I’m sure there were alot more teams than the Flames that were interested. The most any team could offer him was a 2 year ELC, which has a base salary of $900k. He definitely wants to play in the NHL, he turned down on offer from SKA that would make him the second highest paid player on the team behind Kovy for the opportunity.