So the math goes something like this:
Let's say that he can make $2 million a year in the KHL, which is probably too high, but whatever.
He turns down 8 x $8.5M from us.
He plays 3 years in the KHL and comes back as a complete UFA.
In order to break even money-wise, he'd be relying on a team paying him at least $12.4 million per year for at least 5 years, at 27 years old, with only 55 games of NHL equity from over 3 years ago. And if the salary cap rumors are true, the cap will still be $81.5 million.
Good luck with that.