Mack wisely chose the latter, flying in first class for the first time in his life and getting a taste of what life is like in the Majors.
After word got out Sunday evening about a promotion, the Marlins on Monday made official what fans had been hoping for: Miami recalled Mack, MLB Pipeline’s No. 54 overall prospect, from Triple-A Jacksonville to make his Major League debut. He started at catcher and went 0-for-3 while batting seventh in the Marlins' 1-0 loss to the Phillies in the series finale at loanDepot park.
“It's everything that I've worked for my whole career, my whole life, dreaming of this as a kid,” Mack said pregame. “And finally being able to actually be here and do it for fun, and all that stuff, is just really, truly amazing. I thank God every single day for it.”
A 2024 Minor League Gold Glove winner, Mack was slashing .244/.388/.378 with two doubles, three homers and nine RBIs in 24 games. The 23-year-old Mack was also showing better plate discipline, with 22 strikeouts to 20 walks.
COMPLETE MARLINS PROSPECT COVERAGE
Mack, who was originally selected by the organization 31st overall in the 2021 MLB Draft as a three-sport star out of Williamsville East High School in upstate New York, got off to a slow start in his professional career. He slashed just .217/.324/.303 over his first three seasons in large part due to multiple injuries.
Things turned around during the 2023-24 offseason, when Mack changed the way he trained and got rid of some of the holes in his swing. He quickly transformed into the organization’s catcher in waiting.
Mack followed up a breakout 2024 (.806 OPS, Double-A Pensacola MVP) with a strong ‘25 between Pensacola and Triple-A Jacksonville (21 homers and .813 OPS), helping the Jumbo Shrimp capture the International League and Triple-A national championships.
"2023 was the first year that he really had, let's say, failures, or like, some type of adversity," his childhood coach Robbie Bernick told MLB.com. "A lot of high school kids that are drafted aren't equipped with how to handle it, because they've always been the best. So I think a lot of it was at first, just sitting down and saying, 'Hey, how are we going to start training like a professional? If we're really going to do this thing, you really want to make it to the big leagues, you've got to start acting that way now, so that when your time does come, that you're prepared for it. That it's not something that you're shocked by.'"
Miami added Mack to the 40-man roster to protect him from the Rule 5 Draft over the offseason, and he saw substantial reps at big league camp this spring with Agustín Ramírez and Liam Hicks competing at the World Baseball Classic.
During Grapefruit League action, Mack went 3-for-24 (.125) with a grand slam, two walks and seven strikeouts. He felt big league ready but knew his time would come eventually.
The time is now.
Miami optioned Ramírez, who had been struggling both offensively and defensively, as the corresponding roster move to get back on track. Expect to see Mack play with regularity. After all, an organization doesn’t call up a top prospect to ride the bench.
“It's an exciting day [for] anyone making their debut,” manager Clayton McCullough said. “Certainly Joe has earned that from a performance side of things. At least the time I've been here the last couple of years, we've all been incredibly high on the defensive ability and what he brings back there, certainly the receiving and the throwing. And offensively, probably the high school catcher is one of the most difficult positions to develop, and so he's done it at a very quick rate. It just speaks to the talent.”
The Marlins know they’re getting game-changing defense behind the plate. According to MLB Pipeline’s scouting report, Mack has a 60-grade arm (20-80 scouting scale) and a 55-grade field tool.
Since both Mack and Hicks are left-handed batters, they won’t be able to form a platoon like Ramírez and Hicks did. Hicks can also play first base and serve as the designated hitter. According to McCullough, Hicks will start versus right-handed pitching almost every day. When the opposing starter is a lefty, it’ll depend on how the calendar falls and how often guys have been playing.
“They called me up for a reason, and they called me up to be me,” said Mack, who chatted with Phillies superstar Bryce Harper about Buffalo sports while on first base following a fielder's choice in the second inning. “I'm not going to go out there and be somebody else. I'm going to play my game. Nothing really changes. It's the same thing. It's just a bigger stadium in front of more people. They have an expectation of me being me, and me doing what I do best, and that's all I'm going to go out there and do.”