Playing in his first season with the team, Gonzalez has six home runs and 26 RBIs and is batting .237. He is currently mired in a 1-for-19 slump.
New York acquired Gonzalez in January after the Atlanta Braves released him following a trade.
Gonzalez, 36, is making $21.5 million this season on the final year of the seven-year, $154 million deal he signed with the Boston Red Sox in 2011. Since then, he has been traded to the Los Angeles Dodgers, for whom he played more than five seasons, and then to the Braves this offseason. The Mets were on the hook for only $545,000 of Gonzalez's salary this year.
In addition to the Gonzalez news, the Mets announced that catcher Jose Lobaton will be designated for assignment. In corresponding moves, the team said it will call up first baseman Dominic Smith and utility man Ty Kelly from Triple-A Las Vegas.