Yea,he really handled Puig!
I begin by assuming you're not being sarcastic.
He did indeed handle Puig, benching him for the final playoff game and, more generally, resolutely educating him over the past year-and-one-half, often through veteran surrogates like Juan Uribe and Adrian Gonzalez.
But it's not merely Puig. He jerked Matt Kemp out of CF into LF, sat Carl Crawford, then moved Kemp to RF, Puig to CF, and sat Andre Ethier. He routinely sends in a defensive replacement for Hanley Ramirez. All of them have HUGE contracts, but Mattingly is unafraid to confront any sense they have of entitlement. They know he's the boss.
With all his faults, in my opinion Mattingly is MUCH better as Dodger manager than his predecessor, the execrable Joe Torre.