Granderson, who was limited to 61 games in 2013 after breaking his forearm in spring training and a pinkie during the season, turned down a qualifying offer from the New York Yankees.
Granderson's injuries contributed to his worst year with the Yankees as he finished the 2013 campaign hitting .229 with seven homers and 15 RBIs. His OPS was .723.
The veteran outfielder hit 84 combined home runs in 2011 and 2012 for the Yankees, good for the most in baseball over that time period.
Granderson, who turns 33 in March, is one of the top outfielders on the market. Jacoby Ellsbury, Shin-Soo Choo, Carlos Beltran and Nelson Cruz join Granderson among the best available free-agent outfielders.
The Mets did not offer contracts to pitchers Jeremy Hefner and Scott Atchison, infielders Omar Quintanilla and Justin Turner, and utilityman Jordany Valdespin ahead of Monday night's deadline, making the five free agents.
Teams had until midnight to offer 2014 contracts to unsigned players on their 40-man rosters. The Mets have seven remaining arbitration-eligible players, including first baseman Ike Davis and first baseman-outfielder Lucas Duda.
The 27-year-old Hefner went 4-8 with a 4.34 ERA before having reconstructive elbow surgery in August.
Valdespin, 32, hit .188 with four homers and 16 RBIs in 66 games, but he rankled many in the organization with his immaturity on and off the field.
Atchison, 37, only worked 45 1/3 innings because of injuries. He was 3-3 with a 4.37 ERA.
Quintanilla, Turner and Valdespin were the Mets' key backup infielders this season.
Information from ESPNNewYork.com's Adam Rubin and Andrew Marchand and The Associated Press was used in this report.