At 23 years old, Miami Marlins catcher Joe Mack has done something that can be difficult for a rookie catcher in the major leagues: He has established himself.

Mack originally entered the Miami organization as a competitive-balance selection, No. 31 overall, in the 2021 MLB Draft out of Williamsville East High School in Williamsville, N.Y. Nearly five years later, he has become an important part of Miami's present — and potentially an even bigger part of its future.

“What Joe has brought, we've seen it," Marlins manager Clayton McCullough stated about his first-year backstop, according to an MLB.com story from August. "We've seen how our team has been elevated and how we've played, how we've pitched since Joe has been up here, and I don't think that's [a] coincidence. He's been phenomenal.”

The Marlins promoted Mack from the Triple-A Jacksonville Jumbo Shrimp on May 4, and the rookie quickly moved into an important role behind the plate. Through his first 283 at-bats, Mack is hitting .237 with 13 home runs, 47 RBI, and a .691 OPS. The offensive numbers aren't likely to put him at the center of the National League Rookie of the Year conversation, but they tell only part of the story.

Mack's value to Miami has increasingly been defined by what he does with a glove, a throwing arm, and communication with the Fish's pitching staff. In his initial outing in The Show, he's already displaying that he's a well-rounded player.

Mack was a 'bat-first' prospect when he entered professional baseball, but his development behind the plate has become what's helped him craft a fine first season. In 2025, he threw out 33 percent of attempted base stealers and posted a .987 fielding percentage in the minors.

Now, the rookie is doing that work against major-league hitters and pitchers every night.

"I believe I improved on both sides of the plate, hitting and catching," Mack commented about his 2026 campaign. "I've been working a lot on my receiving, my blocking and my throwing. All that stuff has not stopped since the offseason, and my hitting has just improved off of last year.”

Mack may not have the offensive profile to capture a major individual award in his first season. But in the grander scheme of things, that isn't what Miami needed from him. The Marlins needed a catcher who could handle a pitching staff, manage a game, provide dependable defense, and grow into the position. The youngster has done just that — while adding 13 bombs in the stat book.

“Joe really has turned it on [in the second half]," McCullough said. "He's shown that he can get to velocity when he's laying off the pitches down in the strike zone and getting himself into good counts. He has that type of impact and ability.”

For Miami, that's the beginning of something much more important than a rookie campaign. It's the birth of a fixture in South Florida.