The Mets and the Pacific Coast League's Las Vegas 51s officially are partners for the next two years.
The Triple-A club and the Mets have reached a player-development agreement.
The Mets had been affiliated with Buffalo the past four seasons in the International League. Buffalo prioritized winning, whereas the Mets wanted more of a balance between wins and losses and player development, a Mets official said. Still, it was Buffalo's call to part ways.
Toronto, which formerly called Las Vegas home, will take over in Buffalo.
Mets farmhands played Triple-A ball in Tidewater/Norfolk, Va., from 1969 to 2006, then New Orleans in 2007 and '08, followed by Buffalo the past four seasons.
In an unrelated development, Triple-A pitching coach Mark Brewer will not be retained, the Star-Ledger reported.