Scouting Report

Scouting grades: Hit: 45 | Power: 50 | Run: 40 | Arm: 60 | Field: 55 | Overall: 55

Signed for an over-slot $2.5 million as the 31st overall pick in the 2021 Draft, Mack slashed just .217/.324/.303 in his first three pro seasons. He changed his approach in 2024, looking to attack fastballs early in counts, and doubled his previous career total by homering 24 times to rank fifth among Minor League catchers. He's also more athletic than most backstops and now looks like the future starter the Marlins hoped he would become.

Mack's quick left-handed swing and strength produce plus raw power that plays to all fields. He works deep counts and doesn't chase too often, but his approach got too passive at times in the past. He struggles to deal with breaking balls and changeups, so he has compensated by looking to do damage whenever he gets a fastball in the zone, and he did a better job of pulling and lifting pitches last year.

Also a basketball and volleyball player in high school, Mack is agile behind the plate and pounces on grounders in front of him. He has soft hands and has developed into a solid receiver and framer as he has gained experience and improved his focus. He has a plus arm and gets rid of throws quickly, which helped him erase 34 percent of base stealers last season.

Scouting grades: Hit: 40 | Power: 50 | Run: 40 | Arm: 60 | Field: 55 | Overall: 45

One of the top catching prospects in the 2021 Draft, Mack went 31st overall and signed for an over-slot $2.5 million. He has struggled much more at the plate than expected, though the Marlins didn't do him any favors by sending him to High-A at age 20 last year after he missed much of 2022 with a hamstring injury. He batted just .218/.295/.287, with all six of his homers coming in the final seven weeks. 

As an amateur, Mack looked equipped to hit for average and power with a quick left-handed swing, projectable strength and a disciplined approach. In his first three years as a pro, he was overly passive at times and hapless against non-fastballs. He still struggles with breaking ball but is compensating by doing a better job of attacking heaters in early counts while tapping into more power by turning on more pitches than ever.

There still are scouts who believe that Mack has to be better than he has shown in his first three years as a pro, and he has made strides with his defense. He's more athletic than most catchers and moves well behind the plate. He has improved his receiving and his focus and combats the running game with plus arm strength. 

Scouting grades: Hit: 40 | Power: 45 | Run: 40 | Arm: 60 | Field: 50 | Overall: 40 

Mack ranked as one of the best catching prospects in the 2021 Draft after starring on the showcase circuit and leading Williamsville East HS (East Amherst) to the New York Section VI Class A championship in 2021. The Marlins selected him 31st overall that July -- five rounds earlier than his older brother, Charles, went to the Twins in 2018 -- and signed him away from a Clemson commitment for an over-slot $2.5 million. A severe hamstring injury cost him three months and left him at less than his best for much of his first full pro season, after which he made up for some of his lost at-bats as one of the youngest players (age 19) in the Arizona Fall League. 

Mack showed the tools to hit for average and power as an amateur, but they haven't translated into production in pro ball. After he displayed the ability to work counts during a mediocre 2022 season in Single-A, his approach has deteriorated and his swing-and-miss issues have persisted in High-A this year. He still has a quick left-handed stroke and could grow into 20-homer power if he can make more contact and learn to lift more fly balls.

Mack also played basketball and volleyball as a prepster and is quicker and more athletic than most catchers. He has experimented with one-knee and traditional setups behind the plate, and he'll probably settle on the latter because he's more fluid with his receiving and throwing that way. He has the plus arm strength needed to deter the running game, but he needs to improve his focus when he's on defense.

Scouting grades: Hit: 50 | Power: 50 | Run: 40 | Arm: 60 | Field: 50 | Overall: 50 

Mack starred on the showcase circuit, establishing himself as one of the best catching prospects in the 2021 Draft, then led Williamsville East High (East Amherst) to the New York Section VI Class A title last spring. Three years after the Twins selected his older brother Charlie in the sixth round, he went 31st overall to the Marlins last July and signed for an over-slot $2.5 million. He scuffled offensively during his pro debut in Rookie ball, though he did draw 20 walks in 19 games.  

Despite his early career struggles, Mack is equipped to hit for average and power. He slumped at the start of his high school senior season when he dropped his hands too low in his left-handed swing, but he corrected that flaw and displays a disciplined, gap-to-gap approach. His bat speed and projectable strength give him plus raw power and the potential to provide 20 or more homers on an annual basis.  

Mack also played basketball and volleyball in high school and is quicker and more athletic than most catchers. He's agile behind the plate and has soft hands, though he'll need some time to polish his receiving. He features plus arm strength and records sub-1.9-second pop times on throws to second base. 

Scouting grades: Hit: 55 | Power: 50 | Run: 40 | Arm: 60 | Field: 50 | Overall: 50

Williamsville East High (East Amherst, N.Y.) featured the Mack brothers in 2018, with senior Charlie manning shortstop before going in the sixth round to the Twins and freshman Joe playing behind the plate. After repeatedly starring on the showcase circuit last summer, Joe emerged as one of the top catching prospects in the 2021 Draft. He led the Flames to the state Section VI Class A championship this spring, then went 31st overall to the Marlins and signed for an over-slot $2.5 million.

Mack is an advanced hitter with plus raw power. Though he slumped a bit at the start of his high school season when he dropped his hands too low at the plate, he has a sound left-handed swing as well as good plate discipline and a mature gap-to-gap approach. He makes repeated hard contact and has the bat speed and projectable strength to deliver 20 or more homers per season.

Though he's a below-average runner, Mack is quicker and athletic than most catchers. While he needs to polish his receiving, he has good instincts behind the plate and there's no question about him remaining there. He has a plus arm and repeatedly records sub-1.9-second pop times to second base.

Video scouting report »

Scouting grades: Hit: 55 | Power: 50 | Run: 40 | Arm: 60 | Field: 50 | Overall: 50

In 2018, Charles Mack was a high school player outside of Buffalo, New York, who attracted a lot of attention from scouts and eventually signed an above-slot deal with the Twins as a sixth-rounder in that year's Draft. His brother, Joe, was a freshman on that team and even back then, scouts knew he'd be someone they'd be back to see three years later. After standing out at events like the East Coast Pro Showcase and Area Code Games both at the plate and behind it, he has the chance to best his brother in terms of when he gets drafted.

Mack has the chance to be an impact player on both sides of the ball. The left-handed hitter has the chance to be an above-average hitter, showing off an advanced approach all summer with an impressive ability to pick up base hits with two strikes. He has more alley-to-alley gap power, but he has the strength and bat speed that point to at least average power in the future. While speed isn't a part of his game, he's far from a clogger and runs well for a catcher.

All summer, Mack showed off plus pop times to second base, consistently under 1.9 seconds. He'll need to keep working on his overall defensive game, but given his baseball awareness, there's little question he'll be at least a solid average receiver, giving teams a complete package to consider signing away from his commitment to Clemson.

Awards

SOU Player of the Week

Week	Team
04/13/2025

Rawlings MiLB Gold Glove

Year	Team
2024

Transactions

Team	Date	Transaction
	11/18/2025	Miami Marlins selected the contract of C Joe Mack from Jacksonville Jumbo Shrimp.
	07/15/2025	Jacksonville Jumbo Shrimp activated C Joe Mack from the temporarily inactive list.
	07/11/2025	Jacksonville Jumbo Shrimp placed C Joe Mack on the temporarily inactive list.
	07/11/2025	National League Futures activated C Joe Mack.
	04/22/2025	C Joe Mack assigned to Jacksonville Jumbo Shrimp from Pensacola Blue Wahoos.
	03/06/2025	activated C Joe Mack.
	02/10/2025	Miami Marlins invited non-roster C Joe Mack to spring training.
	04/21/2024	C Joe Mack assigned to Pensacola Blue Wahoos from Beloit Sky Carp.
	03/11/2024	C Joe Mack assigned to Miami Marlins.
	03/07/2024	Miami Marlins Prospects activated C Joe Mack.
	04/05/2023	C Joe Mack assigned to Beloit Sky Carp from Jupiter Hammerheads.
	09/16/2022	Mesa Solar Sox activated C Joe Mack.
	09/16/2022	Mesa Solar Sox activated C Joe Mack.
	07/22/2022	Jupiter Hammerheads activated C Joe Mack from the 7-day injured list.
	07/22/2022	Jupiter Hammerheads activated C Joe Mack from the 7-day injured list.
	07/07/2022	Jupiter Hammerheads sent C Joe Mack on a rehab assignment to FCL Marlins.
	07/07/2022	Jupiter Hammerheads sent C Joe Mack on a rehab assignment to FCL Marlins.
	05/24/2022	Jupiter Hammerheads placed C Joe Mack on the 7-day injured list retroactive to May 23, 2022.
	05/17/2022	C Joe Mack assigned to Jupiter Hammerheads from FCL Marlins.
	08/09/2021	C Joe Mack assigned to FCL Marlins.
	07/23/2021	Miami Marlins signed C Joe Mack.
	06/30/2021	C Joe Mack and assigned to College Workout.
	06/16/2020	C Joe Mack assigned to PG National 7 - Navy.
	06/16/2020	C Joe Mack assigned to PG National 7 - Navy.
	07/23/2019	C Joe Mack assigned to 17U National Team Development Program.