Using Statcast Data and Swing Decision Modeling to Identify Underrated Prospects
(12/14/23) Explaining why Orelvis Martinez, Blaze Alexander, and Iván Herrera are currently underrated in prospect rankings.
Originally published on Medium on December 14, 2023.
Constructing a farm system that is able to consistently produce impactful Major League talent, through a combination of scouting and player development, is an integral part of building a sustainably successful Major League Baseball organization. While Major League and prospect ranking organizations alike have become quite effective at accurately ranking and projecting the potential of Minor League players, players outside the Top 100 can still fall on the radar and become impactful pieces to a Major League roster. One such example this past season was Davis Schneider of the Toronto Blue Jays, who despite hitting the ball hard and displaying good plate discipline at AAA, was only ranked as Toronto’s 28th best prospect before posting a 176 wRC+ during his Major League debut at the end of the 2023 season. In my opinion, Orelvis Martinez, Blaze Alexander, and Iván Herrera are three prospects that are currently underrated, and I believe that they have higher ceilings as Major League Baseball players than their prospect rankings suggest at the moment.
Methodology:
Since its introduction to the public sphere in 2015, Statcast data has revolutionized the way Major League Baseball players are analyzed and evaluated. Metrics such as Exit Velocity and Launch Angle have changed the way hitters are evaluated and developed, while improved technology regarding velocity, movement, and spin tracking has allowed for pitching analysis to become more detailed and granular than ever before.
*For deeper insight into Statcast metrics and how they are utilized, check out this piece where I break down my methodology for analyzing hitters and offensive performance*
Starting this past season, AAA Statcast data has been made available to the public, allowing for greater insight to be utilized when evaluating this subset of Minor League players. Similar to how Major League players may underform their batted ball metrics, it is possible for Minor League players to underform them as well and become underrated as a result. Statcast data for Minor League players may also provide insight into which specific areas a player must improve in to either reach their potential or raise their ceiling as a prospect.
Another benefit of the public availability of AAA Statcast data is that public analysts are able to utilize models they have created for analyzing Major League players, and apply them to evaluate prospects. I have been intrigued by swing decision modeling for some time now, as I believe simply looking at metrics such as O-Swing%, Z-Swing%, and Walk Rate either improperly weigh the value of swinging/not swinging at a pitch or don’t tell the complete story about a player’s plate discipline. Drew Haugen from Down By The Farm has created a model that properly weighs the value of swinging/not swinging at a pitch in order to evaluate a player’s swing decisions, and has made the results for both MLB and AAA players publicly available. Further information regarding this swing decision model can be accessed by using the link below:
A Closer Look at Swing Decisions (SwRV)
For this article, in order to identify underrated prospects, I will be using both publicly-available Statcast data as well as the Swing Decision model created by Drew Haugen. I will be focusing on players who consistently hit the ball hard and make good swing decisions, so the following prospect list will be compiled of players who displayed above-average SwRV+ (swing decision metric), Barrel Rate, Max. Exit Velocity, and 90th Percentile Exit Velocity (EV90) during the 2023 Minor League season. This query will also contain solely AAA players (due to data availability) with a minimum of 100 batted ball events, and will only include players 24 years old or younger to account for potential age-to-level advantages. Here are the results of this query:
Given their above-average ability to make good swing decisions and consistently make hard contact, I believe that Orelvis Martinez, Ivan Herrera, and Blaze Alexander are three prospects who should be ranked higher than their current prospect rankings suggest.
Orelvis Martinez (SS/3B — Toronto Blue Jays):
Since being signed as an international free agent by the Toronto Blue Jays in 2023, Orelvis Martinez has done nothing but hit for power throughout his time in the Minors, posting an isolated power of at least .240 at each stop from Rookie ball to AAA. Martinez has also shown noticeable improvements in his Walk and Strikeout Rates over the past two seasons, indicating an improvement in his plate discipline and an ability to adapt from one level to the next, potentially signaling a smooth transition from AAA to MLB in the future.
As shown by the table above, Martinez was able to improve his Walk and Strikeout Rates throughout his tenure at AA, and has continued to exhibit improved plate discipline during his 55 game stint at AAA to end the season. It is also promising to see that his ability to hit for power remained during the transition from AA to AAA, which makes me believe that this will only improve at the beginning of next season and will translate over well to the Major League level.
As shown by the videos above, Martinez displays quite an explosive swing, with a significant leg kick and bat waggle used to generate plus bat speed. It is easy to envision how this swing can generate plus power, and Martinez has shown an ability to pull the ball in the air with high frequency (44.2% FB, 52.7% in AAA last season). FanGraphs’s 2023 evaluation of Martinez was quite bearish on his plate discipline, explaining that “Martinez has long had chase tendencies and difficulty breaking balls, with more refined pitchers taking advantage”. I find this observation really interesting since it appears to contrast with the plate discipline evaluation he has been given by SwRV+. Did Orelvis Martinez improve his plate discipline between the time of the FanGraphs evaluation and his stint at AAA? Does Martinez’s Javier Báez-esque swing create a bias when evaluating his plate discipline? Is SwRV+ simply incorrect? All these theories may be true, but I tend to lean towards the idea that Martinez’s plate discipline is underrated, given the improved Walk Rates and above-average SwRV+ he has displayed during his time at AAA.
One primary concern about Orelvis Martinez is his tendency to swing-and-miss. While it appears that he makes good swing decisions and has shown a demonstrative ability to hit for power, Martinez’s bat-to-ball skills have the potential to hold him back from reaching his ceiling. Martinez produced a 17.7% SwStr Rate and 35.8% Whiff Rate last season at AAA, which indicates that there is a “hole” in his swing that can be exploited by opposing pitchers. I have questions about his bat control and adjustability, as all of the video I have watched of Martinez making impact contact has occurred on pitches located low in the zone. Does Martinez have a “grooved” swing that makes him susceptible to pitches in the upper part of the strike zone? I am not able to watch enough video to make a definitive statement in this area, but I get the impression that this is the case in the limited sample size I have seen of Martinez.
A major component of Orelvis Martinez’s evaluation as a prospect is projecting which position he will play at when he reaches the Majors. Rated as a 40/45 Glove by FanGraphs, Martinez played at 2B, 3B, and SS during his stint at AAA to end the 2023 season. Displaying serviceable fielding ability to be able to play up the middle would be great for Martinez’s prospect value as the bar to clear offensively is lower at these positions than if he were to play at 3B.
Currently ranked as the 88th best prospect in Major League Baseball according to FanGraphs, I believe that Orelvis Martinez should be ranked higher due to his ability to consistently hit for power and make above-average swing decisions. It is promising to see that FanGraphs increased Martinez’s Future Value from a 45 to a 50 in their early 2024 rankings, and I am intrigued to see where he will rank in the updated Top 100 later in the offseason. While a worst-case scenario does exist where Martinez does not improve his swing-and-miss issues, has below-average plate discipline, and is unable to tap into his in-game power, Martinez’s underlying metrics indicate that he can be an above-average offensive player at the Major League level if he is able to improve his bat-to-ball skills, and may hit enough to clear the offensive bar at 3B in the future.
Blaze Alexander (SS — Arizona Diamondbacks):
Since being drafted in the 11th Round of the 2018 Major League Baseball draft by the Arizona Diamondbacks, Blaze Alexander has slowly moved up through Arizona’s Minor League system, reaching AAA Reno for the first time last season. Recovering from a broken thumb suffered in April, Alexander wasn’t able to tap into all the in-game power he displayed in 2022, but was still able to hit the ball hard and make good swing decisions, making it easy to project he will have a bounce back season in 2024 and might earn a Major League call-up in the near-future.
As shown by the table above, Blaze Alexander has made improvements in his offensive approach over the past two seasons which has allowed for him to hit for more power and limit his strikeouts, as evident by the progress he made at AA in 2022. It is possible that the thumb injury robbed Alexander of displaying more in-game power in 2023, but the underlying batted ball metrics indicate that he still hit the ball hard, and his high Walk Rate and SwRV+ indicate that he possesses plus plate discipline which should translate to the next level.
Blaze Alexander displays real raw power that he is able to tap into during games, as evident by his ability to turn on pitches. Alexander utilizes his athleticism to get to pitches low in the zone, as he is able to collapse his lower body in order to make contact with these pitches and tap into his power. Alexander gets into his legs well when he loads, allowing for him to generate power, but has an exaggerated hand movement downwards which may limit his ability to make contact on pitches up in the zone. FanGraphs’s 2023 evaluation of Alexander stated that “readers should still regard Alexander’s hit tool as role-limiting” and the 16.0% SwStr Rate and 35.4% Whiff Rate backs this observation up. Alexander’s load forces him to create extra hand movement in order to make contact pitches in the upper part of the strike zone, and I hypothesize that opposing pitchers may be exploiting this weakness in order to generate swing-and-miss. I am optimistic that a simplification of this hand movement will allow for Alexander to improve his bat-to-ball skills while still retaining his ability to hit for power, since the lower body athleticism he displays in his swing indicates that he will still be able to make contact with and drive pitches at the bottom of the zone, if such an adjustment is made.
Rated as a 50/50 glove by FanGraphs, Blaze Alexander is currently listed as a SS and played 60 games at the position last season for the AAA Reno Aces. FanGraphs’s 2023 evaluation of Alexander stated that he is “a viable defensive shortstop with a huge arm and Alexander hits for enough power when he actually makes contact to be a viable, lower-impact bench infielder”. Gauging by this report, I would feel comfortable projecting Alexander to stay at SS moving forward. While questions regarding his contact ability persist, I believe that Alexander has the potential to be more than a “lower-impact bench infielder” regardless if he improves his contact ability due to his plus plate discipline and ability to hit the ball hard as evident by his underlying metrics. Currently rated as the 31st best prospects in the Diamondbacks system, I believe that Alexander should be rated higher even with his current contact issues, and can potentially make a Davis Schneider-like impact upon arrival to the Major Leagues if he is able to limit his swing-and-miss going forward.
Iván Herrera (C — St. Louis Cardinals):
Iván Herrera has long been expected to be the successor to Yadier Molina as the catcher of the future for the St. Louis Cardinals since being signed by the organization as an international free agent in July 2016. With the signing of Willson Contrearas to a 5 year, $87.5M contract last offseason, Herrera’s future as a catcher, especially with the Cardinals, may be in doubt despite the above-average offensive production he has displayed throughout his professional career.
As shown by the table above, Iván Herrera has done nothing but produce throughout his tenure at AAA Memphis, combining his ability to hit for power with very good plate discipline. Herrera’s ability to make good swing decisions particularly stands out, as evident by both his 107.9 SwRV+ and 20.8% O-Swing at AAA in 2023. While Herrera has been able to tap into his power throughout his stint in the Minor Leagues, he has yet to hit a home run during his brief tenure in the Majors.
As shown by the videos above, Herrera displays quite a unique batting stance, using what can be best described as a “rigid” load before unleashing his powerful swing. Reminiscent of Matt Olson’s load, Herrera’s hands hang out away from his body before moving back inward at time of launch. In addition, Herrera begins with an open stance before moving his front foot inward at the same time he initiates his hand movement. Given the results he has seen at the Minor League level, I would assume this motion is repeatable but it does not look like an “athletic” stance, hence the “rigid” description.
As is the case with all catching prospects, Herrera’s defensive value will be critical to both his prospect evaluation and his Major League potential. FanGraphs currently rates Herrera’s defense as a 35/40 and believes that “[his] defense has plateaued and remains below average across the board”. This raises questions when evaluating Herrera’s value as a prospect given the defensive bar that needs to be crossed in order to be a productive catcher at the Major League level.
There is no doubt, in my opinion, that Herrera clears the bar offensively for being a productive (if not, above-average) Major League catcher, however there are questions as to whether or not he can produce enough offensively to make a potential positional change to 1B worthwhile. While simply a very small sample size, Herrera has run into some ground ball issues during his time in the Majors, producing a 57.7% Ground Ball Rate during his call-up in 2023. Could a swing path adjustment allow for him to loft the ball more and tap into more of his power? Regardless, Herrera displays enough offensive upside for a catcher that I believe he should be ranked towards the back of the Top 100, if not on the fringes of it, with room to rise up the rankings if his defensive abilities were to improve. With the Cardinals only in Year 2 of their contract with Willson Contreras, I am curious to see if Herrera will be utilized as part of a trade package for another rotation upgrade (possibly to the White Sox for Dylan Cease?), especially since he is running out of option years. Either way, as a catching prospect with an ability to hit the ball hard and make good swing decisions, St. Louis will give Iván Herrera as much developmental runaway as possible to improve his defensive abilities and given his batted ball metrics and swing decisions, I still believe he has the potential to be the catcher of the future for the Cardinals.
Concluding Thoughts:
Due to their ability to make good swing decisions and consistently hit the ball hard, I believe that Orelvis Martinez, Blaze Alexander, and Iván Herrera are three prospects that are currently underrated, and I believe that they have higher ceilings as Major League Baseball players than their prospect rankings suggest at the moment. I find it interesting that two out of the three prospects that I selected (Orelvis Martinez and Blaze Alexander) have significant swing-and-miss issues, which makes sense considering that I did not filter for Whiff Rate or Swinging Strike Rate. If I were an organization that had a player development system with a good track record of developing bat-to-ball skills, I would be intrigued at the idea of acquiring Orelvis Martinez or Blaze Alexander since they can significantly raise their ceilings as a prospect if they are able to improve in this area.
I believe the biggest takeaway of this article is explaining how to utilize advanced metrics in order to identify a specific way in which a player can improve. By filtering for above-average swing decisions and exit velocity, this query was able to identify players who could significantly raise their ceilings if they improve their bat-to-ball skills. Maybe a future query can filter players with above-average swing decisions, above-average bat-to-ball skills, and below average exit velocity in order to identify Minor League players who should train with weighted bats to improve their bat speed. These aforementioned examples underscore the impact that utilizing Statcast data and advanced metrics can have on evaluating and developing prospects, and teams that are able to use this data efficiently in evaluating prospects throughout their entire Minor League system will have a competitive advantage when it comes to consistently producing impact Major League talent.
Follow @MLBDailyStats_ on X (Twitter) and Adam Salorio on Substack for more in-depth MLB analysis. Statistics provided by FanGraphs, Baseball Savant, Thomas Nestico’s Patreon, and Down By The Farm.
Photo Credits to Getty Images, Mark Taylor, Alex Weiner, and El Paso Chilhuahuas.