We’ve been doing this every year for nine seasons.
My guess... I don't see the Mets making any changes here through Duda's arbitration period unless he gets hurt. He will be eligible for free agency in 2018 which lines up perfectly with Smith's ETA.
Me? I'd run this move very differently if, like Alderson says, he has salary flexibility. Duda is one of the few (rare) sluggers in the National League and I would take free agency off the table by signing him to a 4-year (through 2018) contract for around $28mil.
The Mets look very good here.