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2023 MLB Draft: Breaking Down Six Standout Pitching Prospects From Jupiter

Kyle Johnson (Stacy Jo Grant)
Two-way player Kyle Johnson (Stacy Jo Grant)

Hudson Belinsky was Baseball America's lead draft writer from 2015-2017 before spending five years with the Arizona Diamondbacks as an area scout, covering Georgia and Northern Florida. He is the signing scout for 2022 No. 2 overall pick and the top player on BA's draft board, OF Druw Jones.

Perfect Game’s WWBA Championship in Jupiter attracts many talented pitchers. Countless times in my career scouting in Jupiter, I’ve rolled up to a field and seen a kid with ordinary (or poor) fastball velocity and a good offspeed pitch or two who turned out to be really, really good later on—Dustin May and Chase Dollander are two recent examples who come to mind.

To put this event in context, Jupiter is usually the last event many top amateur pitchers participate in prior to shutting down for the winter months. We also see pitchers throwing in short spurts in Jupiter; their stuff can (and often does) look very different when they are in a starting role in their official high school seasons.

In some cases young pitchers are worn out, don’t have a routine, or are off of their routine at the end of a long season. For a pitcher, proper warmup, rest and recovery are essential, and the nature of fall travel baseball makes proper nutrition another challenge that holds young pitchers back. The opposite can also be true—sometimes pitchers struggle to maintain their routines when they get away from the structure that their travel program provides in the summer and fall.

Jupiter is one piece of the puzzle. It’s a useful event for organizing targets and determining which “on the bubble” high school pitchers warrant further looks and consideration heading into the spring. It’s not definitive in determining a pitcher’s draft stock, but it can lead to a pitcher being scouted much earlier the following spring. Here, we’ll break down some pitchers who showed promising traits in Jupiter. To varying degrees, each of these players will receive some professional consideration coming out of high school. 


Chance Mako (East Rowan HS, Salisbury, N.C.) showed impressive stuff, stamina and athleticism. He’s got a lot of traits that teams look for in starting pitching prospects. The North Carolina State recruit has a loose, fluid arm action and an ultra-projectable 6-foot-6 frame. Many young pitchers of that height struggle to repeat their deliveries, leading to inconsistent location and movement. The ability for a pitcher to stay coordinated and get their body into the right place in spite of mechanical deficiencies can give clues as to their level of body control.

Mako appears to have made some quality adjustments since the summer. Generally, he’s gathering more of his weight in his heel and glute, giving himself more balance and stability before his front foot strikes the dirt. His stride is shorter, leading to some tendency to lose his direction and finish towards the first base line. He has some head movement at release, especially when his direction isn’t aligned towards home plate. As Mako matures and gains core strength, in addition to improving his stamina and direction, his head whack should dissipate.

Mako’s fastball worked in the low 90s (averaging 92, according to Synergy), showing quality life through the zone and peaking at 94 mph early on and then again in his final inning of work. His primary offspeed pitch was his slider (80-83 mph), which showed sharp break glove side. As he gains strength, both of these pitches have plus potential.

Mako’s slider shows tight spin out of his hand, but its shape varies based on his landing and direction. To his arm side, Mako’s slider can show more of a top-to-bottom break, while showing more 11-to-5 or 10-to-4 shape when thrown to his glove side. While it could be much more consistent, Mako can spin this pitch with some present feel. He also dropped in a more traditional 12-to-6 curveball in Jupiter, further speaking to his body control and feel to manipulate the baseball.

Synergy has tracked 161 of Mako’s pitches in 2022. Only five of them (3%) were changeups. Despite very limited usage, Mako showed an impressive feel for his changeup in Jupiter. He sells it from the same arm slot as his fastball and generates late, heavy tumbling action. This pitch projects to pair well with his slider. Throwing both a four-seam fastball and a two-seam fastball will lead to even more deception for this type of changeup, which appears to be a standard circle changeup. His low usage indicates that he may have even more upside with it. He’s less likely to have practiced different ways of gripping or releasing this pitch in specific locations and situations.

Mako is far from a finished product, but this is what the really good pitchers tend to look like at that age. He’s showing growth as a strike-thrower, moving more efficiently on the mound and showing the upside for a deep arsenal of above-average pitches. A little more progress heading into the spring could launch Mako into early round discussions next summer.


Kyle Johnson (Riverside HS, Leesburg, Va.) is an intriguing two-way prospect committed to Duke. On the mound, the southpaw has an athletic, up-tempo motion. He’s loose and twitchy, with good direction and a quick, compact arm action. His fastball shows riding life up, especially arm side. He peaked at 92 mph and sat in the upper 80s throughout five shutout innings for the Dirtbags travel organization. He showed a sharp, sweeping breaking ball and attacked the zone in Jupiter. He flashed a heavy circle changeup as well, and that pitch shows a lot of promising indicators: Johnson throws it with quality arm speed and generates late tumble. It’s not a substantial part of his arsenal yet, but he busted it out for a swing and miss against Brandon Winokour.

Johnson’s delivery is athletic and repeatable and he creates good hip-shoulder separation. He’s well-suited to gain velocity and improve his command and deception with some minor adjustments to his motion. Johnson breaks his hands a bit late, and drops his glove hand forward as he loads the ball directly behind his body. That appears to get him moving off his balance point quickly, and he lands slightly closed to stay balanced at finish. Some purposeful work with his glove hand could stabilize him over the rubber a bit longer, giving his arm enough time to load properly before foot strike. Johnson has good body control and shows the ability to get himself into the right position to locate his pitches, but he has a habit of getting to foot strike prior to stacking his wrist above his elbow, which leads to some misses high and/or arm side.

Johnson’s athleticism and lefthandedness will attract scouts to his games next spring. He’s one to keep an eye on and monitor for a jump in the spring. There are a lot of good traits here, and he’s not just a pitcher who hits—he’s a righthanded-hitting power/speed player as well.


Mac Heuer (Homeschool, Ga.) is a physical righthanded starter. He has a balanced, repeatable delivery with good direction towards home plate. His arm action is compact and he’s able to repeat his three-quarter arm slot consistently.

Heuer showed the ability to spot his fastball to his arm side consistently, inducing quality sink and arm-side run. Heuer located a sharp breaking ball for uncomfortable called strikes. The Texas Tech commit pitched primarily with his fastball in Jupiter—30 of his 33 pitches were heaters, and Heuer attacked the zone with the pitch. He has solid present velocity, and his ability to command the fastball should enable him to have immediate success at the next level, be that college or professional baseball.

Despite limited usage, Heuer showed feel to locate a low-80s slider, freezing two hitters for called third strikes and getting a lefthanded hitter to roll over another. He’s shown potential with a more traditional curveball in the past, a mid-to-upper 70s offering with more depth. Regardless of which breaking ball Heuer leans on in the spring, his feel and growth in this area are positive indicators of how Heuer’s slider and/or curveball project to develop moving forward.

Heuer’s delivery is functionally sound with a repeatable stride that allows him to generate power through his hips and pelvis. Heuer projects well as he continues to gain strength and explosiveness in his lower half.

Heuer appears close to “maxed out” physically, but his body type and movement patterns, in addition to his ability to spin a firm breaking ball for strikes, indicate continued development of velocity. His shorter, more repeatable stride creates a bit less extension, allowing the late movement of his fastball to create more deception as it approaches the hitting zone. Heuer is on the rise this fall, and continuing on his upward trajectory and performing in a starting role could push Heuer into early-round consideration next summer.


John Glasscock (Fluvanna County HS, Palmyra, Va.) has an athletic, repeatable delivery. He’s consistently balanced and maintains good direction to home plate. His fastball showed excellent life at the plate, dancing through the hitting zone at 90-92 mph. Glasscock also showed the makings of a plus slider, with devastatingly late 10-to-4 bite, as well as a more vertical curveball that snapped through the zone at 76 mph.

Glasscock, a West Virginia commit, has the frame, athleticism, and feel to manipulate the spin of the baseball to develop into a starter at the professional level. There’s still room to fill in his 6-foot-1 frame, and his arm speed and hand speed indicate continued growth of his stuff as well. He doesn’t throw overly hard yet, but Glasscock projects to develop a plus fastball long term—both in terms of movement and velocity. The upside here is undeniable, and Glasscock could jump from good to great quickly.


Boston Flannery (Brunswick School, Greenwich, Conn.) is physically advanced, with a muscular 6-foot-4 frame. He has a quick, whippy arm action, and shows potential for a quality fastball and firm, vertical breaking ball. Flannery appears to be a quad-dominant loader; at the top of his motion, he’s moving quickly and sinking his weight into his quad, rather than balancing himself with his glute and “riding his hip” down the mound. This leads to a heavy landing out on his front foot. To stay balanced, Flannery cuts off his landing at times, giving him a deceptive release to righthanded batters, while also inhibiting his ability to command his pitches to his glove side.

Some attention to his gathering phase could unlock even more velocity in Flannery, while also enabling him to improve his direction and stay behind his fastball. Flannery peaked at 94 mph in Jupiter and pitched at 90-92. His fastball shows late life through the zone and better direction should improve the vertical break of his fastball, which would pair better with his firm, low-80s breaking ball.


Lefthander Brayden May (Whitefield Academy, Smyrna, Ga.) impressed in Jupiter, striking out three in two clean innings of work against a strong USA Prime Team. His ability to spin his curveball and slider are elite—for high school or college—and his changeup shows above-average potential as well. He pitched at 86-88 mph with his fastball, but the pitch shows life from May’s high arm slot. While he has below-average velocity (for now, at least), May’s fastball pairs well with his offspeed pitches.

He’s got an athletic, deceptive delivery and throws each pitch from the same slot. In addition to his high arm slot, rising heater and hammer breaking balls, May creates deception with a long stride and a collapsed front leg at landing. It’s an unusual look for hitters—a high slot and lower release height.

May is committed to Tennessee. This type of pitching prospect doesn’t usually command a big bonus out of high school. If May isn’t drafted and signed, he’s likely to be a quick contributor to the Volunteers’ already elite pitching staff. Pitching coach Frank Anderson has a strong track record of developing this type of pitcher, historically, and in his time at Tennessee.

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