2021 MLB Draft: Prospects With Interesting Data

Written by: Mason McRae (@mason_mcrae)

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Every new draft cycle is a race to identify top draft prospects; even more so than most seasons, the shortened 2020 spring makes not only makes finding reliable data increasingly difficult, but finding numbers (velocity, exit velocity, in-game performance) you can typically utilize to paint a better picture of a 20-year-old can be like searching for a needle in a haystack for evaluators hoping to map out their pre-college baseball season boards. While draft boards in July don’t make much (if any) of a difference a year from now, it’s always interesting to follow the path of each draft’s top guys through a calendar year.

After getting my hands on data for dozens of draft prospects, a handful have separated themselves with specific elite characteristics that make their profiles interesting. Some players have more meaningful data then others, and some of the names below might not be of any interest to you for a variety of different reasons (mechanics, arm action, lack of velocity).

Pitch design and movement are still utilized sparingly in draft evaluations around the industry, but its usefulness shouldn’t be confused with the ability to write a report on a player with only data. Seeing a player, speaking to a player, getting the feel for makeup and plenty of other things a trackman device can’t record still matter, so all data should be used with discrepancy. Data is usually an indicator of how a pitcher should optimize his offerings; pitchers with lower spin rates and movement can certainly be effective, but you can usually get a sense of certainly organizational targets by examining active spin and movement profiles. 

Before we dive into the specific players, here are some hot words that will only become increasingly popular as advanced analytics become more prevalent throughout the evaluation process and amongst organizations.

Spin Rates: The basis behind the data is rather simple. Higher spin rates (fastball/breaking balls) correlate to higher swinging strike numbers, at least more so than velocity. But raw spin rate has somewhat become a dinosaur number, as the relevance to future success isn’t as prevalent as vertical approach angle and movement profiles. Every one knows what spin rate is as it’s the easiest way to appear knowledgeable in the data world, but the meaningfulness of the metric isn’t as important as one would think. The point: use spin rate with discretion; it’s certainly an ingredient in what could be a tasty dish, but alone it’s fairly inedible.

Vertical Approach Angle: Higher vertical movement on fastballs typically represents the ability to pitch up, combining that with lower release heights and approach angles present a flat angle for the ball that allow the illusion of ‘rise’ on a pitch. This goes back to the correlation of spin rates to swinging strikes as higher spin rate fastballs are more prominent at the top half of the zone opposed to the bottom half, where high horizontal movement sinkers are more effective. Vertical approach angle is going to become an incredibly popular data point over the next few years. The differences between a very flat VAA (<4.3) and average VAA (5.6 – 5.3) can potentially be catastrophic. Side Note: VAA is typically a negative number (it’s rare for a pitch to have an upwards trajectory at zone entry, hence why it’s a negative number), but for the sake of making it more presentable, people will usually type it out as a positive number.

Induced Vertical Break: The efficiency of a pitcher’s fastball up in the zone can, generally speaking, come down to the ability to generate heavy vertical movement (induced vertical break) at the top of the zone. Still not as prominent of an indicator for future success, IVB is more of a ‘where to pitch’ talking point, not an overall attestation that pitchers will consistently get outs at the next level. Pitchers with lesser vertical movement are generally more effective down in the zone – through generating ground balls – but their success rates aren’t as high. IVB is a popular tool to assess a pitching prospect’s ceiling. 

Release Height: Standing alone, release height holds very little meaning. Paired with high vertical movement, it’s vastly prevalent in pitch design. Lower release heights coupled with flat approach angles generate higher swinging strike rates. Players with release heights under 4.9 usually get massive whiff rates up in the zone and can get away with having a steeper curveball shape, though guys with higher release heights typically are sinker-ballers who utilize sliders with gyro movement.

Extension: Perceived velocity has been a new advancement in the numbers world, basically the baseball equivalent of ‘what it feels like’ versus the actual temperature in the weather world. Like you can probably assume, longer extensions from the mound are generally better, but be mindful that those same extensions also directly correlate to shoulder related issues (added pressure) for pitchers. Being able to get long extension simply creates a shorter flight on the ball and less time for a hitter to react.

Horizontal Movement: The final piece to the puzzle, horizontal movement is one of the least meaningful numbers as it’s more accustomed to sinker-ballers who pitch down in the zone producing higher ground ball rates. For pitchers who lack spin, vertical movement, and ride on their fastball, going into a sinker style approach with the fastball is a way to be efficient even with less desirable fastball characteristics.

Now, let’s dive into some data for the 2021 draft class.

Rodney Boone, LHP, UC Santa Barbara

Probably the most fascinating arm in the class, Boone possesses a ridiculously flat VAA (3.9). Throwing from a 5.3 release height and producing around 25 in of IVB is an easy plus pitch, and most models will put a 70 grade on it. Unfortunately, a max of 90 mph on his fastball is suboptimal. Typically working in the 86-87 range later in outings, Boone will need to get higher velocity to climb on boards, but teams who draft players based on approach angle alone (TB, BAL, HOU) should already have Boone high on their boards. His fastball/changeup duo combined for a 17.6 SwStr% in 351 pitches this past spring. His curveball is a bit slurvy, which couldn’t be farther from the spin axis he should have to optimize the backspin on his fastball. A tilt around 4:30 on the hook would better pair with the fastball and arsenal tunneling. Boone is a name to watch heading into the 2021 collegiate season. 

Jack Leiter, RHP, Vanderbilt

There’s a bit of disparity in Leiter’s underlying data depending on who you ask, but my latest source had the top prospect at a VAA under 4.5 and into the 3.8-4.1 range at times. In the case he does legitimately have a 3.8-4.1 VAA, Leiter’s in the upper percentile for that category. Combining his ridiculously flat ball flight with well above average IVB (19.5) and a lowish release height outline one of the best fastballs you’ll see from an amateur, even at an average release speed of only 92 mph. Leiter’s probably the most optimized arm in the class. An industry source said his club had a near perfect score on his delivery out of high school because of his arm deceleration, hand/ball position at foot strike and movement patterns. Leiter’s kinetic sequencing points to an easy operation, one that puts as little stress on his muscle fibers (every pitch thrown causes muscles to tear, but ability to cause less wear & tear is heavily valued by models) as one could. Leiter’s curveball is another optimized offering that perfectly complements the fastball with an ideal spin axis. On its own, Leiter’s curveball is a vanilla offering, but it’s the similar characteristics (trajectory, ball flight, tunnel) that make it such a unique third offering. Leiter’s average raw spin rates are largely drowned out by his extension on the fastball (6.6-6.8) and his perceived fastball velocity is probably closer to 95 mph, on average. If he comes out sitting 94-95 next spring (96-97ish perceived velocity), his fastball could peak as an 80-grade pitch rather than a 70-grade.

Ian Moller, C, Wahlert HS

Moller is quite literally the most optimized hitter in this class. LAs on BIP around 19-20° and EVs into the triple digits, as well as average EVs around 93-95 that are highly coveted by models. He’s one of the most advanced hitters in the class, with vertical bat angles in the 25-30 range combined with the loft generated by the fantastic LAs producing hefty results. His frame – from a historic perspective – is an ideal body proportion (6’1, 200 lbs). If he weren’t a part of such a rough demographic, he’d epitomize a model darling.

Brady House, 3B, Winder-Barrow HS

House is a picture perfect prospect from a model’s perspective, touting hefty LAs (14-15°), monstrous EVs (max of 105, averages around 91-92), and fantastic body/bat tilt/angles at contact/launch position. His youth—combined with fictitious arm bend—are the cherry on top. House’s front leg stability (Trout like) is spearheaded by a violent back leg. Put all of it together and you’re looking at quite possibly the most pro-ready amateur hitter in the class. House is probably every organization’s Build-A-Bear version of an amateur hitter as his body proportions and data would’ve been enough to get him drafted in the top-10 in 2020 at exactly 17-years-old.

Ryan Cusick, RHP, Wake Forest

From a traditional standpoint (command, mechanics), Cusick isn’t on a single team’s radar based on the eye test alone. Fortunately, Trackman will likely save teams from missing out on an highly optimized arm. An IVB of 19.1 is elite, as is his 4.9 VAA. Cusick’s release height is 5.9, which isn’t ideal, but his approach angle really makes up for it. Spin rates upwards of 2,400 rpm and an ideal spin axis are two numbers hard to teach. Cusick’s fastball data is phenomenal, and throwing the pitch on average at 92.9 mph is incredible with his 6.7 extension. It’s a relief profile more than likely because of no third offering and a fringe second pitch – a slider with around 2,150 rpm but decent movement (close to no vMov, heavy hMov). It’s only August of 2020, but I wouldn’t surprised if Cusick were a Tampa Bay Ray in less then a year.

Kumar Rocker, RHP, Vanderbilt

Rocker’s data is fun. Extension is over 7.0 on the fastball, IVB’s around 18.5, spin rates around 2,245 rpm, and a VAA under 4.4 makes it easy to throw plus grades on the pitch, though the actual outcomes of the pitch (including a swing-and-miss rates just below 9.0%) are a cause for concern. His velocity is elite (93-95, T98) and the perceived velocity likely gets into triple digits and sits in the 94-96 area – because of long extension – but those are merely rough estimates with the data in front of  me. His slider is also an interesting pitch as it’s got average raw spin (2,290 rpm) but ideal movement (zero vMov, some hMov). His changeup is a sneaky good pitch (1,700 rpm) with heavy vertical movement (-7.0) and spin rates in the optimizable range relative to the fastball. Because of his advanced extension (top percentile) you can wash a lot of the other data away as his average velocity (94.5) is perceived much higher thanks to the fantastic extension. Rocker’s curveball (35.0 SwStr%) is a weird pitch as the movement isn’t special, but it plays off the fastball/slider combination well. The right-hander’s ability to tunnel all four pitches allows the entire arsenal play better than each pitch’s specific data would suggest.

Jackson Jobe, RHP, Heritage Hall HS

It’s hard to paint an entire picture on Jobe without the entirety of his data, but raw spin rates of 2,500 rpm on the fastball and 3,150 rpm on the slider create a massive foundation for a player development staff to build on. Organically increasing raw spin is extremely difficult, hence the emphasis on pitchers who already possess it at an above average rate. Part of the reason Jobe is such a perfect prospect for a developmental staff is his lower half inefficiencies and un-athletic posture at release, two somewhat easy ways to unlock power and stability in a delivery. From face value, it seems he’s got a relatively steep release, which isn’t ideal at all. Thankfully, he’s far from a finished product from a mechanical standpoint, and the rawness in his delivery is evident.

Danny Watson, RHP, VCU

Watson is a wildly inconsistent pitcher, but when he’s at his best, there’s elite fastball characteristics that play up in the zone. To this point, the right-hander’s inability to command his fastball in the upper-portion of the strike zone has minimized the effectiveness of the pitch. A vertical approach angle that’s typically around 5.1 is slightly flat. However, at his best, he’s usually around 4.8 which is a tough plane out of the hand of a 6’7 frame with a 5.8 release height. Part of Watson’s unoptimization is his lack of extension (6.0 on FB) relative to frame. The right-hander’s ability to spin it and extreme youth (20.6) are the reasons the lack of consistency can get a pass for the time being. Spin rates around 2,408 rpm on the fastball and 2,609 rpm on the slider are well above average, but Watson must be more consistent while throwing the two pitches to ascend to the next level of his development. Eye-opening raw spin rates can’t be taught, and induced vertical breaks over 20″ are uncommon, though he’s typically around 17″.

Follow P365 MLB Draft Analyst Mason McRae on Twitter! @mason_mcrae

Follow us on Twitter! @Prospects365

Featured image courtesy of photographer Joe LeBlanc and Good Eye Photography


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