Smackin' Mack! Marlins backstop shows off big league readiness with grand slam

February 24th, 2026

JUPITER, Fla. -- About a month ago, caught veteran right-hander Max Scherzer’s bullpen at nearby Cressey Sports Performance.

Moments like that, settings like the Spring Training big league clubhouse and swings like his grand slam on Tuesday afternoon in the Marlins' 6-1 victory over the Phillies at Roger Dean Chevrolet Stadium make Mack believe he is big league ready.

“With all the confidence I can say, ‘I know I'm ready,’” Mack said. “I've done the work, I've put in all the hours, I've done everything that I need to do, and my faith in Jesus is also something that propels me to look forward to every day, because I know that I'm ready. I know that I have confidence, and nobody's going to take that away from me.

“I know that being in this clubhouse is a great sign, and nothing's given to me, so I've still got to earn it. I just come every day with the mentality to compete and do my best, be my best self."

After left-hander Andrew Walling hit his second batter of the fifth inning, Mack took a pitch above the zone and then swung through another. When Walling left a third consecutive cutter over the plate, Mack sliced it just over the left-field wall for a two-out oppo shot.

According to Statcast, the homer traveled a projected 336 feet with an exit velocity of 97.3 mph, a 32-degree launch angle and a hang time of 5.1 seconds.

Mack, who ranks as MLB Pipeline’s No. 62 overall prospect, crushed 21 homers in 112 combined games between Double-A Pensacola and Triple-A Jacksonville last season. He also added 22 doubles and two triples.

“My strong side is the back side, so just staying with it that way, and not trying to do too much with it,” said Mack, who redeemed himself after a back-pick throwing error scored a run in the first. “I kind of just got it good.”

The left-handed-hitting Mack is a unique player in this age of baseball, where catchers rarely contribute above-average production on both sides of the ball.

After earning the 2024 Minor League Gold Glove for catchers, Mack saw an uptick in his errors from one to 11 in ‘25. While his steal-to-strikes and throwdown percentages remained relatively consistent, his blocking needed work. So Mack focused on that over the offseason, refining his move for receiving pitches to all quadrants of the strike zone – and even outside of it. He focused on cutting down on the strikeouts and impacting the ball more.

Instead of going back to upstate New York, Mack spent the entirety of his winter at Cressey with the likes of Scherzer, the Marlins' Braxton Garrett and Tyler Phillips, Phillies shortstop Trea Turner and Tigers veteran Justin Verlander.

“I think Joe's super talented and does a lot of things really, really well,” catching coach Craig Driver told MLB.com before camp began. “It's a pretty unique package of receiving ability and ability to catch and throw in a super athletic package.”

How the remainder of spring and the early part of the season unfold will be interesting to monitor.

Second-year players Agustín Ramírez and Liam Hicks remain the top two catchers on the depth chart, but Mack will do his best to make it a tough decision. Both Ramírez and Hicks will leave camp in a few days to participate in the World Baseball Classic, giving Mack more regular opportunities than last spring when he received just 19 plate appearances in 10 games.

Mack understands the situation. Everyone inside the clubhouse is competing for a job. There’s no animosity. He can’t worry about what others are doing.

“It's probably still the most demanding position on the field,” manager Clayton McCullough said. “Any type of offense you get from that position, in a lot of ways, you look at as a real bonus. Joe has, we believe, the chance to impact on both sides of the ball. He's a terrific thrower, there's a lot of athleticism and creativity with how he can throw, and the confidence he has back there to do that as well as layering on the type of receiver that he is [is unique].

“Offensively, he [has] power from the left side. [There’s] a lot to like there with Joe. Great for him. Any young player here early in camp to have some success just continues to add to their confidence that they have, that ‘I belong here and can play here.’”