MIAMI -- The J.T. Realmuto sweepstakes appear to be entering the final stages.A source told MLB.com on Thursday that trade talks for the Marlins' All-Star catcher are in "advanced stages," with four clubs still in the mix: the Padres, Reds, Dodgers and Braves.MLB Network insider Jon Paul Morosi on Wednesday

MIAMI -- The J.T. Realmuto sweepstakes appear to be entering the final stages.

A source told MLB.com on Thursday that trade talks for the Marlins' All-Star catcher are in "advanced stages," with four clubs still in the mix: the Padres, Reds, Dodgers and Braves.

MLB Network insider Jon Paul Morosi on Wednesday night reported that the Padres "are more of a factor" than the Dodgers.

It's hard to gauge if there is a clear frontrunner, but if there is, it may be San Diego. The Reds also have been aggressive in recent days. Atlanta has been lurking all offseason, and it has had conversations with the Marlins for more than a year.

Barring a team jumping in more aggressively, there is a clear Final Four for Realmuto.

Realmuto has been a hot topic the entire Hot Stove season. Initially, the Marlins had hoped to offer him a contract extension, but shortly after the World Series, his agent, Jeff Berry of CAA Sports, made it public that his client was not interested in a long-term deal in Miami.

At least 14 clubs this offseason expressed some level of interest in Realmuto. The Astros and Rays recently were still active, but they appear to no longer be in the equation.

Throughout the process, the Marlins have held firm on their high return for arguably the top catcher in the Majors. They are seeking a package of two-to-four players, with at least a top prospect or two included.

Realmuto, 27, is entering his prime and is coming off his finest power season, batting .277 with career highs in home runs (21) and RBIs (74).

The Padres have a deep farm system that includes switch-hitting catcher Francisco Mejía , ranked 26th overall on MLB Pipeline's Top 100 prospect list. However, there are some questions about Mejia's defensive abilities behind the plate, which may mean Miami sees him as more of an outfield prospect, because there is a belief he will hit at the big league level.

A major concern for the Marlins in this process is finding a catcher to replace Realmuto. With a young pitching staff, it is a necessity. Realmuto and Chad Wallach , who has limited big league experience, are the only two catchers on Miami's 40-man roster. San Diego does have Austin Hedges , who has been in the big leagues since 2015 and could potentially be part of a deal.

The Reds also have a deep system, and the Marlins have discussed outfielder Taylor Trammell (ranked 16th overall) and third baseman Jonathan India (53rd). Cincinnati has a proven big league catcher in Tucker Barnhart , who could be part of a potential trade, as well.

The Marlins and Dodgers have discussed catching prospect Keibert Ruiz, rated No. 36. Atlanta also has a loaded farm system, and veteran catcher Tyler Flowers could be included in a trade.

Realmuto, an All-Star for the first time in 2018, was in his second season of arbitration this winter. He will make $5.9 million in '19, and he will qualify for free agency after the '20 season.

Recently, the Padres asked for a window to discuss a contract extension for Realmuto, but the Marlins denied that option to San Diego and any other interested club.