As the Marlins' rebuild continues, star catcher J.T. Realmuto's future with the club remains increasingly uncertain -- specifically in the words of his agent, Jeff Berry of CAA.

Speaking on MLB Network Radio on Tuesday, Berry made it clear that Realmuto, who is under club control through 2020, won't sign a long-term extension with Miami.

"I think he will definitely be wearing a different uniform by the start of Spring Training," Berry said.

Earlier this month, Marlins president of baseball operations Michael Hill told MLB.com's Joe Frisaro that the club intended to reach out to Realmuto's camp to discuss a potential extension.

"It's no secret, I think J.T. knows how we feel about him. … As I've said consistently, we want him to be a part of what we're doing in the long term," Hill said at the time.

But Realmuto has long been a speculative trade chip, given his multiple years of club control, his age (he'll turn 28 in March) and the fact that he emerged as arguably the top offensive catcher in the Majors last year. He posted a slash line of .277/.340/.484 with 21 homers and 74 RBIs over 125 games while earning his first All-Star appearance.

The Nationals were publicly linked to Realmuto last winter and again ahead of the July 31 non-waiver Trade Deadline, but they couldn't strike a deal. The Braves have also been rumored to be interested in Realmuto to bolster their promising young lineup and provide stability at the position long term.

Realmuto is among the last players left in Miami after the club's fire sale last offseason that included trades of National League Most Valuable Player Award winner Giancarlo Stanton to the Yankees, two-time All-Star Marcell Ozuna to the Cardinals and Christian Yelich -- the favorite to win the NL MVP Award for 2018 -- to the Brewers. Realmuto had reportedly requested to be traded last winter, according to MLB Network insider Ken Rosenthal.

Realmuto is eligible for a salary increase through arbitration to roughly $6.1 million, according to estimates from MLB Trade Rumors. Realmuto lost his arbitration case last year against the Marlins and earned $2.9 million.