Sure, but he sucked at it.
He would churn through a bunch of backend guys and never really give them a chance. Ex., Jeffress became a stud like as soon as Toronto got rid of him. Same with Chavez. There are other names littered in the recent bullpen history of the Jays that should have been given more of a chance. Coello, Colt Hynes, Dyson, Wagner, maybe Rasmussen
The only buy-low or bounce back RP type that I can think of that worked out in AA's entire tenure is Hendricks... maybe Delabar was a buy-low? More of a fair deal.
He bought on guys with Saves experience like Hawkins, CoCo, Francisco, Santos, Lyon.
He overpaid for guys with good scouting grades, like Esmil Rogers and Brad Lincoln.
He brought SP prospects up from A ball out of desperation to fill bullpen needs.
I really don't think AA was too good at playing the reliever game.
Smart teams like Tampa turn free again bargains into shut down relievers on the regular, man. Like, yearly.