The annual return of spring training in Major League Baseball represents a lot of exciting things, but the most beautiful aspect in my opinion is how much fans get caught up in the nonsense of it all. Grainy footage of live batting practice sessions. A hitter experimenting with a slightly different stance at the plate. A pitcher’s average fastball velocity going up 2 MPH after his first outing. A pitcher’s average fastball velocity going down 2 MPH after his first outing! Developments like this are not meaningless in themselves, but every year, so much of what fanbases devote their emotional energy to during spring training is inconsequential by season’s end.
Another fun part about this time of year is the chance to see the game’s most exciting prospects face major league competition, and for more astute fans, to examine their up-to-the-minute Statcast numbers during these spring games. Luckily, all AAA ballparks are equipped with Statcast technology, so advanced metrics are publicly available for prospects while they’re still in the minor leagues! Using this wonderful tutorial from Robert Frey, I recently scraped pitch-level Statcast data for the entire 2024 season using Python. Here are five young hitters that I’m intrigued by going into spring training in 2025, based on their AAA metrics in 2024. Overreact accordingly.
1. Johnathan Rodríguez, OF (CLE)
Key stat: 106.4 MPH 90th-percentile exit velocity
When looking at the AAA Statcast power-hitting leaderboards, Rodríguez is a name that immediately jumps off the page. Among all hitters at that level aged 26 and under with at least 100 batted balls on the season, his 90th-percentile exit velocity places third behind James Wood and Junior Caminero. His hardest-hit ball of the season was a sizzling 116.8 MPH, a mark that was topped only by Caminero, Pedro León, and fellow Guardian Jhonkensy Noel.
Rodríguez, now 25, got his first taste of big-league action last spring in the form of a brief 13-game stint in which he didn’t make too much noise (63 wRC+). You also won’t find the former third-round pick near the top of any major outlet’s list of best Guardians prospects. Swing-and-miss is a concern, as evidenced by his below-average zone contact rate at AAA and his 35% strikeout rate from his time in the majors. However, he knows how to take a pitch, and the overall approach was enough to snag him MVP honors at AAA’s International League last season.
Rodríguez also turned heads when Fangraphs released their projections for 2025. Various systems are conflicted on what to make of him, but for what it’s worth, ZiPS is forecasting a 112 wRC+. OOPSY, their newest model, has him at 110. His path for playing time is unclear as of now, which is what makes this such a big training camp for him.
Cleveland will have Lane Thomas, acquired at last year’s trade deadline, roaming the outfield for a full season along with the always-electric Steven Kwan. Will Brennan and Tyler Freeman are also ahead of Rodríguez on the depth chart, and Kyle Manzardo is likely to see the bulk of available reps at DH. We also can’t forget Noel, who certainly earned more goodwill than Rodriguez did during his debut season. He’ll have to push through a logjam to earn a roster spot, but just like so many other hitters looking to prove their worth over these next few weeks, therein lies opportunity.
The Guardians are rightfully viewed as one of the more resourceful franchises in the game, but their biggest organizational challenge the past few years has been finding offense to support José Ramírez. Interestingly, they have a long track record with prospects like this: Big, strong, power-hitting corner outfield types. Franmil Reyes and Oscar González didn’t work out, and they’re hoping Noel can become what guys like that were supposed to. Rodríguez is another one from that mold who has a pretty good chance to break through, seeing as it doesn’t get much better at AAA than he was. The past few iterations of successful Cleveland teams always seem to have a couple relative unknowns who have a coming-out party with the bat – don’t be surprised if Johnathan Rodríguez is one of them this time around.
2. Jacob Wilson, SS (ATH)
Key Stat: 98.9% Zone Contact%
Just a year after being drafted sixth overall and flying up the A’s minor-league ranks, Jacob Wilson made his debut in Oakland last year, notched his first MLB hit in his first game – and strained his hamstring rounding the bases, requiring a trip to the injured list. He made it back in time for the end of the franchise’s final season at the Coliseum, and good thing, because he’s supposed to be a big part of their first one in Sacramento. Fangraphs’ depth charts project Wilson for 546 plate appearances in 2025 – and to finish second on the team in WAR behind only Brent Rooker.
Why so bullish? For starters, no, you are not misreading the italicized text under this section’s heading: Jacob Wilson made contact on 98.9% of his swings in the strike zone. To put that into context, one of the trademarks of being an elite contact hitter is not missing on swings in the zone. A select few hitters – only a handful – will ever post a zone contact rate over 90% in any given season. Luis Arraez, the one hitter in baseball that has made a living off hitting for average above anything else, has a career zone-contact rate of 93.8%. Wilson was a decimal point away from 99% at AAA last year. He swung and missed at 1% of pitches over the heart of the plate as well. Both these marks obviously led all AAA hitters with that 100-batted-ball threshold.
Sample size is obviously important to consider here. The A’s called him up to AAA after just 22 games at AA, and he only played 26 games there before being moved along to the big club. It’s unlikely that he comes in and leads the league in hits and average, but the fact that it’s even a remote possibility for someone who was drafted less than two calendar years ago with just 103 MLB plate appearances to their name is a testament to the unique skillset Wilson possesses.
As with most players of this archetype, his power numbers lag behind and his plate discipline isn’t that impressive either – you can’t notch all those hits without being a little bit of a free swinger – but it would also be unfair to simply label Wilson a slap hitter. His AAA batted ball data indicates an above-average rate of pulled fly balls and an optimal distribution of contact between 95 and 105 MPH, which are two traits essential for outpacing expected home run totals based on exit velocity. He also racked up 28 doubles across just 226 minor-league plate appearances last year.
The Athletics are somewhat aimless at the moment, set to call a minor league park home for the next few years and no confirmed date yet for their much-anticipated move to Las Vegas. Wilson, Baseball America’s 38th-ranked prospect in the game, should be a fixture for whatever comes their way next.
3. Nacho Alvarez Jr., IF (ATL)
Key Stat: 6.0 hitting run value/100 PA
Few teams are looking for some get-back quite like the Atlanta Braves will be this season. Armed with reinforcements that should be coming off the shelf from injury at various points throughout the season, they figure to be a lot closer to the 104-win powerhouse they were a couple years ago than the one that barely managed to limp into the postseason last year.
As far as the offense goes, the one noticeable weak spot on the depth chart was shortstop. For all he can do with the glove, Orlando Arcia was not an imposing presence with the bat in 2024 (72 wRC+). The Braves have a young gun by the name of Nacho Alvarez Jr. that might put Arcia on the hot seat if that doesn’t change.
Nothing from his player card above instantly catches the eye until you consider that he did this all at the age of 21. According to Baseball Reference, the average age of a AAA hitter is a little over 26 years old. The only 21-year-olds with more than 100 batted balls at that level last season were Alvarez, Jackson Holliday, Jasson Domínguez, and Caminero. Alvarez’s offensive contributions were worth 17 runs of value, prorated to roughly 6 per 100 plate appearances. Both these figures led that group of hitters. Alvarez slashed .297/.368/.463 and struck out 45 times compared to 37 walks, which are very good results regardless of context, but he did it at age 21 in AAA.
Braves fans have something to be excited about, and what’s even more encouraging is the fact that there aren’t obvious red flags after digging deeper into the metrics. He has the makings of a versatile threat at the plate – he didn’t chase too much, he didn’t miss on his swings in the zone, and his success there did not come at the cost of power.
Amidst the slew of injuries, Alvarez was able to dip his feet into big-league waters for eight games last summer. He only went 3-for-30 with three singles, and no indication has been given as of now that Arcia’s spot as the team’s primary shortstop is in danger. However, if Atlanta finds themselves looking to add a jolt to their lineup midseason, the best solution could very well come from within.
4. Adrian Del Castillo, C (AZ)
Key Stat: 11.4% Barrel%/BBE
The Arizona Diamondbacks have a conundrum on their hands. A couple of seasons ago, they traded for Gabriel Moreno, their catcher for the future. He was a hit, winning a Gold Glove in his first full season in the show and helping to lead the team to a shocking berth in the World Series. He was piecing together another solid season in 2024 before an injury limited him to just 97 games on the year. Healthy again, Moreno should be one of the premier catchers in the game in 2025.
What the Diamondbacks were likely not prepared for when they made this trade was this kind of emergence of Adrian Del Castillo, who was a flat-out hitting machine everywhere he played last season. Del Castillo was a second-rounder in 2021, so they undoubtedly had high expectations for him, but at age 25, he burst onto the scene after Moreno’s injury, posting a 146 wRC+ in 25 games. This was inflated by a cartoonish .438 BABIP and a 91-point difference between his wOBA and his xwOBA – Fangraphs projections see him straddling the line of being a league-average hitter in 2025, which is probably fair – but at the same time, there isn’t much left for him to accomplish in the minors.
Arizona’s AAA affiliate, the Reno Aces, play at a hitter-friendly ballpark in the thin desert air. As such, the following numbers should be taken with a grain of salt, but it’s still worth mentioning that Del Castillo hit 26 home runs and slashed .312/.399/.603 in 105 games at that level in 2024. The underlying numbers back it up well – his 11.4% barrel rate was second among all AAA catchers aged 26 and under with at least 100 BBE to only Detroit’s Dillon Dingler. He hit the ball very hard and he hit it in the air, plain and simple.
Strikeouts were an issue once he got to the big leagues (32.2% strikeout rate), and they have been in the past, as his first AAA stint in 2023 saw him go down on strikes 28.9% of the time. However, his AAA strikeout rate in 2024 was down to 16.9%, so he has proven he can work on this issue. His defense at catcher was subpar in the big leagues, but his bat should net him some more playing time there this season. If the D-Backs choose to keep him at the position, this could be one of the more dangerous backstop tandems in the game throughout the near future.
5. Jace Jung, 3B (DET)
Key Stat: 16.1% BB%
The Tigers’ farm system is viewed by most as one of the best in baseball. They had seven prospects listed in Baseball America’s top 101 report from this winter; only the Rays (9) had more. Of those seven, Jace Jung was ranked the lowest at 97th, which says more about how deep Detroit’s prospect pool is than anything else – Jung was the 12th-overall pick just three years ago, and he seems no worse for wear following offseason wrist surgery.
This is bad news for the pitchers he faces this year, because patience is a strength of his. Among qualified hitters, Jung’s 16.1% walk rate placed fifth in the International League in 2024 and eighth in AAA as a whole. His 21.2% chase rate ranked 14th among 26-and-under hitters with at least 100 BBE, his rate of swinging from behind in the count was 47.5% which was also on the lower end of that group, and he put up an above-average barrel rate to back it up. This makes for an interesting profile for someone who Fangraphs projects will take up the majority of playing time at third base for a young and motivated Tigers team that’s looking to build off a surprise playoff run.
Of course, no prospect is without flaws, and Jung could stand to benefit from some further refinement to his approach. While he kept on walking without a hassle, he did strike out a hair over 30% of the time during his 34-game cup of coffee at the big league level last season. At AAA, he missed on 13.8% of his swings on pitches down the heart of the plate, and 8.3% of his batted balls were popups – both of which are a little high for my liking. Being in the 21st percentile of AAA hitters in zone contact rate wasn’t ideal either.
Despite that, his advanced ability to see pitches and work the count should put him ahead of most of his peers by the time he establishes himself in the big leagues, and his raw power was given a 60 grade on the 20-80 scale by Fangraphs on their midseason report from 2024. He’ll be exciting to watch all spring, and if the Tigers can take another step forward in 2025, he’ll likely have something to do with it.
All percentile visualizations are my own. Raw data pulled from Baseball Savant.