The Marlins made it clear Realmuto would be promoted back to the big leagues after he took part in the Suns' playoff run. Jacksonville completed a three-game sweep of Chattanooga on Saturday night.
As part of his development, the organization wanted Realmuto to experience playoff fever.
"It means a lot," the 23-year-old said. "That experience, the only way to get that is to play in those games. That's real important going on in my career, playing in games that mean something, being able to deal with those pressure situations. That means a lot."
Realmuto batted .346 (9-for-26) in the playoffs, and .299 with eight homers and 62 RBIs in the regular season.
Realmuto received some playing time with the Marlins, appearing in seven big league games.
The Marlins are carrying three catchers, with Realmuto backing up Jarrod Saltalamacchia and Jeff Mathis.
"J.T. gives us an option and flexibility to be able to pinch-run for Salty or Matty," Miami manager Mike Redmond said. "It does give you more of a comfort level. J.T. is an athlete. He runs probably better than our other catchers."
Down the stretch, Realmuto could get a few starts, depending on the situation.
"I'd love to get him in there for a game or two, for sure," Redmond said. "We'll see down the road. I know he's had a tremendous year. They won the championship there. He's done a great job. I'd love to get him in there, but we'll see where he fits."
Joe Frisaro is a reporter for MLB.com. He writes a blog, called The Fish Pond. Follow him on Twitter @JoeFrisaro. This story was not subject to the approval of Major League Baseball or its clubs.