
At ages 18 and 19 entering their first professional seasons, many were surprised to see righty Eury Perez and lefty Dax Fulton assigned as high as the full season ranks to begin 2021. The teenage twin towers have risen to the task. Now, they are being challenged again.
On Monday, Craig Mish of the Miami Herald reported that the 6’8” righty Eury Perez and the 6’7” lefty Dax Fulton have been promoted from A Jupiter to A+ Beloit. The amount of growth both Perez and Fulton have shown in such a short period of time in their very young careers despite some unique individual circumstances is not often seen at this level of competition.

RHP Eury Perez
56 IP, 1.61 ERA, 0.95 WHIP, 82/21 K/BB
A 2019 international signee at age 17, Perez inked with the Marlins for $200K. According to MLB Pipeline, he first began to garner attention when he participated in the instructional league last year as he was effective against older competition. That attention grew during spring training this season. In May, Perez made his pro debut against the St Lucie Mets as the youngest player in all of Minor League Baseball. Facing off against competition four years older than him on average, Perez has been very difficult for the Low A Southeast to handle. In 56 innings, he has a ridiculously minuscule 1.61 ERA 0.95 WHIP, 163 BAA and 82/21 K/BB. Among players with at least 50 IP, Perez’s ERA ranks second in all of MiLB. Additionally, within the Marlins organization his WHIP also ranks second. His 27.5% K/BB% leads all Miami pitchers.
As good as Perez has been all year long, he’s really come on of late. In his last four starts, Eury hasn’t allowed a run in 18 IP. On August 7th, he struck out a career high 11, attributing to a 32/5 K/BB. Over that span, he only gave up one single hit. There has been one major mechanical adjustment to thank for Perez’s recent run of dominance that led up to his call to Beloit.
Earlier this year, we noticed a considerable difference in Perez’s level of effort depending on which pitch he is throwing. While Eury has always repeated his arm slot and release points well, he had a tendency to throw with a considerably large amount of intent behind his heater, a middling amount behind his change up and a very soft amount behind his breaking pitch. While his plus plus stuff was able to keep him effective in the low A ranks, higher level competition would have been able to pick up on Eury’s tips and time him. Watching Eury in person during the aforementioned 11 strikeout performance, this hole seems to have been closed. Here is Eury’s delivery of his fastball, changeup and curveball in May compared to the aforementioned no-hit performance:


Masking his arm speed and repeating his delivery more consistently has been a huge cog for Perez as he has continued to improve through more prolific dominance. When you’re 6’8”, there are a ton of levers and a lot of body to get to work in unison at the same time. The fact Perez is doing so 56 innings into his pro career and making his long limbs unravel and fly at hitters with much better repetition, thereby cleaning up one of few present weaknesses and should have him as a top 10 organizational prospect immediately and a top 100 prospect in baseball in very short order.
Perez, whose numbers very early on in his pro career are drawing comparisons to some of the brightest young teenage stars to ever grace the Miami Marlins organization, will join the Beloit rotation for what project to be a handful of starts before he reaches his innings limit.

LHP Dax Fulton
58.2 IP, 4.30 ERA, 1.36 WHIP, 66/30 K/BB
Fulton, 19, receives his promotion after an abbreviated start to spring training. After undergoing Tommy John in his senior year of high school before being selected by Miami in the second round of 2020, the Marlins were cautions with Fulton but he was still able to convince the front office he deserved the promotion to full season ball to begin 2021. Truth be told, it wasn’t a great start to Fulton’s minor league career as he gave up 10 earned runs in his first 13.2 innings in the month of May. June was a bit kinder to Dax as he worked 15 innings on the same amount of damage. In July, Fulton finished five innings for the first time in his career, a great confidence booster, but he still embarked on the month of August with an overall 5.22 ERA by way of a 1.62 WHIP, a 48/40 K/BB and quite a bit to figure out.
In August, Fulton has been a completely different animal. Each of his first two starts in the second-to-last month of the season have been nearly identical and just as spectacular. In each outing, he worked five innings, allowed just one hit. He struck out a combined 18 and, after allowing 20 walks in his 28.2 IP, did not walk a single hitter.
So what has been the difference for Dax? It can be broken down to two things: consistency in control and in his stuff and, like Eury, better knowledge, control and incorporation of his body.
At the start of the year, Dax’s fastball was sitting 90-93 with the ability to ramp up to 95. There was room for more heat if he could incorporate his lower half into his delivery more. That has happened lately. In his 10 K performance, Dax sat 93 and hit 96. On top of the velocity, the placement of the pitch has been much better of late and he’s been consistently hitting his spots. He’s also showing the confidence to elevate it for strikes.

Fulton’s primary breaker has become a vicious power curve that has natural shape and bend due to a supremely high release point. He’s improved the vertical movement on that pitch as the year has gone on: at the start of the year, his average spin rate was in the 2500 range. Lately, he has been spinning up in the 2600s on average and, per Ian Smith of ProspectsLive who has seen him throw in person frequently, has been up over 3000. He can both place the pitch on the corners for strikes and bury it in the dirt out of the zone with intent and get guys (such as Jasson Dominguez) to look foolish with it.

Fulton’s third pitch is a high 80s changeup that has the ability to touch 90. He has done a ton of work with that pitch season, building it up from a pure mix-in pitch at the start of the year to a pure weapon. Via a better feel and much easier release than seen previously, Fulton can paint with this pitch and its late two plane fade.

While Fulton has always had the blueprint for really good stuff, it has improved because of his ability to begin to incorporate his legs into his delivery more lately, stepping downhill with a longer stride to shorten the distance to the plate more advantageously and turning his front leg into his delivery more. He’s also learning how to push off his plant leg better which has been the catalyst for the added velo.
Overall, though Fulton is less polished than his younger teammate Perez, he has his arm built up and his legs are starting to follow suit. Though it was a bit more surprising to see this promotion, Dax, like Eury, has made stark improvements in a short period of time al following a comeback Tommy John surgery. If he can continue to learn how to put his entire frame behind his pitches, polish off his finish and maintain the consistency we have seen lately against A+ competition, there’s capacity for Fulton’s stuff to play even better and for him to become a top tier prospect both organizationally and league wide.
Fulton, like Perez, is 58.2 IP into a likely 75-100 IP limit.
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