7th/8th inning guy paired with Venters. replaces Durbin, so huge gain for the bullpen. with him + Venters+Kimbrel, and O'Flaherty and Gearrin as backup righty/lefty specialists, that bullpen will be best in the majors again.
Hanson has been on a serious decline path, with his fastball losing velocity every year. He projects now to be an average starter, who will likely suffer a significant injury at some point. But if he recovers his fastball he'll be an ace, albeit he's never been a pitcher that went deep into games. And this is his first arb year, so if he rebounds he'll be under team control for another 3 seasons. and only earns ~$4M this year. great gamble if you need starting pitching, which the Braves didn't.