The blues want significantly more than a 4th. They already said they aren't dealing him even for a third. I don't see him wanting to spend the next 6 years fighting to barely make the playoffs.

There is no way the Blues trade his rights for a fourth.

$9m for six years is $54m, not $63m. Pietrangelo isn't signing for $54m when he has a $64m offer on the table. You can't give him $45m in signing bonuses in the first three years because of contract structure rules. The player isn't likely to want massive money up front because the players are certain to lose 30% of their salary next year, he'd probably want it structured so that the big money starts year three, when escrow is capped at 10%.