The deal, in catcher Posey's first year of arbitration, represents a big increase in his previous salary of $615,000 with the World Series champions.
Posey posted a National League-leading .336 batting average and had 24 home runs and 103 runs batted in after coming back from ankle surgery in 2011.
The team also agreed to new deals with rightfielder Hunter Pence, reliever Jose Mijares and outfielder Gregor Blanco, according to the website.
Pence's one-year contract is for $13.8 million. (Reporting by Simon Evans in Miami; editing by Gene Cherry)