The best free agent catcher on the free agent market this offseason is Yasmani Grandal — But he is not the best catcher available.

Marlins All-Star catcher J.T. Realmuto has been expected to be traded since Derek Jeter started his tag sale last offseason, but he is still in Miami. According to his agent Jeff Berry, though, he will most likely not play another game in a Marlins uniform.

“I think he will definitely be wearing a different uniform by the start of spring training,” Berry said Tuesday on SiriusXM radio.

“J.T., he’s informed the Marlins ownership, the front office he’s not going to sign an extension in Miami,” Berry continued. “From that standpoint, you can keep him for two years or not. It makes sense, when you have one of the most valuable trade assets in baseball, to move him.”

Realmuto, 27, would be an immense upgrade over any of the Mets options. Their best in-house catcher is Travis d’Arnaud who is coming off Tommy John surgery and is arbitration eligible this offseason. Kevin Plawecki and Tomas Nido are the next best options, none of whom compare favorably to Realmuto.

In his first All-Star season, Realmuto hit .277/.340/.484 with 21 home runs and 74 RBIs with a 4.3 bWAR and 4.8 fWAR. He is also an outstanding defensive catcher, throwing out 38% of would-be base stealers in 2018.

If there is anything a Mets catcher needs to be good at defensively, it’s helping to quell the running game as teams have run wild on the Mets in recent years. Perhaps relying on a catcher coming off Tommy John surgery is not the best idea.

Realmuto would solve many problems. The Mets don’t have any real catching prospects in the pipeline, and trading for him now would give them a good opportunity to lock him up long term. He would give the Mets a good defensive catcher for the first time in recent memory, while also adding a strong bat to the middle of the line-up.

There has been doubt that the Mets would trade for Realmuto, something new General Manager Brodie Van Wagenen commented on in his first press conference.

“I think we’re going to be aggressive in talking to all players, and frankly, be aggressive in talking to other teams about looking at some players that we’re interested in and find a match in terms of trades,” he said.

An important tidbit to point out is that Realmuto’s agent, Jeff Berry, is employed by CAA Sports, where he and Brodie Van Wagenen worked together for many years. While this would not have as much effect on a trade, it could when it comes to signing a long-term contract.

If the Mets don’t get Realmuto, the only other acceptable catcher upgrades available would be Yasmani Grandal (30) and Wilson Ramos (31). After them, are free agents such as Kurt Suzuki (35), Martin Maldonado (32), Nick Hundley (35), Matt Wieters (33), A.J. Ellis (38), and Devin Mesoraco (31).