The air is feeling cooler and baseball diamonds have become vacant across the country as football season is in full swing. It feels like it was just yesterday that we had baseball to liven up our daily lives. After an exciting postseason with our new blood colored sock overlords, we now must wait until the snows begin to thaw before we get to hear that sweet sound of wooden bats cracking. Alas, the season is over and while the hot stove has yet to begin crackling there is still work to be done.

Thousands of players are in the minors that are to be evaluated for their future stock and potential impact on the highest level of the game, which they hope to reach at some point. Many of these prospects get their start in rookie ball. Rookie ball is often a player’s first taste of professional baseball. Rookie ball features everything from International players aged 16-20 playing for the first time outside of their home country to recently drafted High School players leaving home for the first time.

This off season, I have tasked myself with looking at the top 20 stateside Rookie ball performances for players under the age of 20 and evaluating them to see if their performance is a sign of things to come or simply a hot streak against inexperienced competition. This will be a 4-part series, looking at 5 players at a time. This is so that I can spend ample time studying these players and their results to make fair and educated conjectures about them. The reason I chose to limit the pool to players under age 20 is to avoid college players who are typically more advanced than high school players or J2 players playing stateside for the first time. I have also omitted players performing in the Dominican Summer League as the stats from that circuit are often more inflated than stateside side rookie leagues and there is very little scouting information available on DSL players. The top 20 rookie ball performances were determined by our Seasonal Hitter Statistical Rankings.

Before proceeding with the players, I want to preface this series with the premise that Rookie Ball stats are generally a poor indicator of future big-league success. According to a study done by our statistical guru Chip Borne (@ccbournejr), in a five-year sample from 2008-2012 there were 230 players registering a Rookie Ball wRC+ value of over 150 (an average performance would be 100 wRC+). Of those 150 players, only 16 would go on to have seasons at the big-league level totaling a WAR of 2 or greater:

Players with a WAR totaling about 2 are generally average big-league regulars. So, only 16 players of that original 230 player sample became big league regulars or better. For reference, Chip also did the same study regarding A+ and AA leagues. There were 145 and 144 players with seasons over 150 wRC+ in A+ and AA ball respectively. There were 39 players from A+ and 40 players from AA went on to produce at least one MLB season of 2 or greater WAR. Doing the math that means only 7% of rookie ball performers totaling a 150 wRC+ season or better went on to be a big-league regular or better as compared to 27% and 28% of such players in A+ or AA.

This study shows us that Rookie Ball performance is not a perfect indicator of future big-league success. So the question becomes, why look at it at all? This is where the adage of “don’t scout the stat line” comes in. A majority of my analysis will be more scouting influenced and watching tape rather than looking at the stats. Do scouts I trust in the industry and my own evaluations match what the player is doing in rookie ball, or is there reason to skeptical? It’ll be hard to evaluate these performances, but my hope is that I can possibly unearth some gems before they gain real traction in prospect circles and further prove with some players that Rookie Ball isn’t a perfect indicator of future success.

Frainyer Chavez, 19 SS TEX

League PA AVG OBP SLG HR SB BB% K% ISO BABIP wOBA wRC+ Arizona 196 .306 .378 .405 2 23 9.7% 18.9% .098 .375 .375 125

Frainyer Chavez is a switch-hitting SS drafted in the 22nd round of the 2018 MLB draft out of Midland Texas Junior College by the Texas Rangers. By all accounts he’s a great defensive player with all you want in a short stop (quickness, hands, arm, etc.). He has a good quick swing that can generate contact but probably won’t develop much power. He had an impressive professional debut showing speed with 23 SB. There isn’t a lot of tape on him that I can find at the moment (I was able to find a video of him from 2015 when he was 16 but there’s only so many conjectures I can make from that tape), so I can only give secondhand accounts for the time being. When asked if Chavez “is just a guy?” Eric Longenhagen from Fangraphs responded with “I like him. He’s small, but the swing works and he has good pop for his size, feel for all-fields contact. Looks more like a utility type right now, but that’d be a great outcome for a pick that late”.

Verdict: Not Much Brewing Here

I think at best he’s a utility player, as Logenhagen noted. He had a great debut but he’s going to have to keep hitting through the minors if he wants to be re-evaluated. Not worth even a speculative add in dynasty leagues right now.

Freudis Nova, 18 SS HOU

League PA AVG OBP SLG HR SB BB% K% ISO BABIP wOBA wRC+ GCL 157 .308 .331 .466 6 9 3.8% 13.4% .158 .317 .366 120

Freudis Nova is probably my favorite player out of this first batch of rookie ball highlights. Originally signed by the Marlins in 2016 but was then released after a failed PED test. The Astros grabbed him in 2017 to an impressive $1.2 Million and had an okay start to his professional career in the Dominican Summer league the same year. In 2018, he had his stateside debut in the Gulf Coast league and proved why he was worth that $1.2 Million even after concerns of the failed PED test. Nova is premium athlete with plus speed and a very strong throwing arm that allows him to make all the plays from short. I think he’s more than capable to develop into an above average defensive SS but with Correa (and Bregman) at the Major League level, the Astros have already been trying him out at 3B and 2B. With the strong throwing arm, he would profile better at 3B but has the athleticism to play 2nd as well. The Astros will test him at other positions but look for them to develop him as SS for the majority of his development.

Nova has a pretty swing with a decent sized leg kick but gets the leg down and is able to generate terrific bat speed producing surprising pop. Nova has the chance to develop both an above average hit tool and above average power. One thing to draw back on is his aggressive approach. A BB% of only 3.8% is incredibly low and indicative of an aggressive hitter without a refined approach at the plate. While the K% isn’t high now, as he progresses and faces better pitchers who are better equipped to expose aggressive hitters, it won’t come as a surprise to see the strikeouts start to rack up. Another point that a Prospect Live’s Ralph Lifshitz made in their Houston Astros’ top 30 prospects is that he struggled against left handed pitching, slashing only .208/.286/.458 against southpaws. It’s odd for a right-handed hitter to struggle so mightily against lefties, so that is something worth keeping an eye on as he progresses.

Verdict: Cautiously Optimistic

Nova has a ton of talent and is a premium athlete. I’m a believer that he should develop into a player with a plus hit tool with 20+ home run pop but need to see improvement in his approach and his performance against left handed pitching before I’m willing to bet the house (shouldn’t ever considering putting too many eggs in a rookie ball prospect). He should be a target in most dynasty formats.

Kristian Robinson, 17 OF ARI

League PA AVG OBP SLG HR SB BB% K% ISO BABIP wOBA wRC+ Arizona 182 .272 .341 .414 4 7 8.8% 25.3% .142 .351 .357 114 Pioneer 74 .300 .419 .467 3 5 14.9% 28.4% .167 .405 .401 131

Kristian Robinson is probably one of the more well-known prospects that will show up in this series, as several scouts have raved about his potential since his signing last year. Only 17 years old (will turn 18 in December) and just completed his first professional season stateside in both the Arizona and Pioneer leagues. Overall the results were good, showing a solid power-speed profile but with strikeout issues. He was signed out of the Bahamas in 2017 by the Arizona Diamondbacks and immediately became one of the crown jewels of their system.

He has all the tools you’re looking for in a young prospect. He is currently 6’3” and 190 lbs with some room to grow. He has a lean athletic frame that should retain his athleticism as he matures. He currently has plus speed that should remain even as he matures, which will allow him to become at least an average CF. There is some disagreement about his throwing arm as some sites scout it as plus (Fangraphs) while John Eshleman from 2080 Baseball states “His arm is still developing, fringy at present, but added growth should get it to average.” He has a great amount of raw strength at 17 years old and it will only grow. As is the problem with several young prospects is how will the hit tool develop? There’s a lot of holes in his swing, I personally think his hands start to high and it causes a longer swing. He’s already posting 25+ K% in Rookie ball and the pitching talent will only improve as he moves on.

Verdict: Must Watch

Overall Robinson’s debut was everything people were hoping for. He is more physically developed than much of his competition and it showed at times but so did his un-molded swing that has yet to fully tap into his raw power. His upside is tremendous as Matt Thompson from Prospects Live compares him to White Sox super prospect Eloy Jimenez. He’s a guy that based on ceiling alone he’s a must own in most dynasty formats, but the hit tool will need to develop if he wants to reach his ceiling.

Yorlis Rodriguez, 19 3B SFG

League PA AVG OBP SLG HR SB BB% K% ISO BABIP wOBA wRC+ Arizona 183 .323 .409 .445 2 6 10.4% 13.7% .123 .369 .408 144

Yorlis Rodriguez was signed out of Cuba in July of last year and skipped the Dominican Summer league to make his stateside debut. Honestly, there isn’t a lot of information available on Rodriguez at the moment. He put up good numbers in his stateside debut but as I stated in my preface, numbers at this level aren’t a perfect indicator of future success. I was able to find one video on him but it’s from batting practice, so I can only decipher the swing I see in a non-competitive environment. The first thing that stands out to me is the good bat speed and the ball definitely jumps off the bat. The bat path is a little long as his hands start high at the start of the swing then has to come down to finish through the zone. He looks physically mature for his age and at about 6’0” 187 lbs, he’s probably close to maturity, so the raw power won’t progress much more than what it currently is.

VERDICT: Not Enough Information

There just isn’t enough information on Rodriguez at the moment to make a judgment on whether his rookie ball performance is something to look at more closely or not. He looks more physically developed than a lot of kids at that level that I’ve seen so it’s possible he’s just taking advantage of less developed competition. I’ll place him in the “Keep an eye out for” column for next year for now.

Mark Vientos, 18 SS NYM

League PA AVG OBP SLG HR SB BB% K% ISO BABIP wOBA wRC+ App 262 .287 .389 .489 11 1 14.1% 16.4% .202 .312 .402 132

The Mets drafted Mark Vientos in the 2nd round (59th overall) in the 2017 MLB draft. After splitting time in the Gulf Coast League and Rookie Ball his first year at only 17 years old, he returned to Kingsport for his second go around in the Appalachian League for his age 18 season. He is currently listed at 6’4” and 185 lbs with plenty of room to grow into his frame. Unfortunately, if you are looking at him as another great SS prospect you might be disappointed. Even right now he is a below average runner and fielder at the position and that is well before his body matures fully. The Mets have already realized his future and in 2018 played only at 3B with no appearances at SS so his SS designation will soon change. Defensively at 3B, he seems to have average instincts and shows good hands. His arm is strong enough to make all the throws from third from the little video I’ve been able to find on him so he should stick to 3rd long term.

Offensively I’m a pretty big fan of the swing. He has a quick swing with strong wrists that creates good bat speed through the zone. There is some natural loft to his swing that should lead to more homers as he matures. In the video below taken by 2080 Baseball’s John Eshleman, Mark shows good patience at the plate and can lay off pitches in the dirt. This is backed up by his BB% and K% which are good indicators of a good feel at the plate. He also displays good power off the bat, mostly to left field, but is able to drive the ball to right. It’ll be interesting to see how his power develops as he matures. If I had to give him grades for his raw power I’d place it at 50/60, I think there is a lot of room on his frame for weight which should lead to an uptick in raw power. That raw power should translate well in game with the natural loft already in his swing but will obviously depend on his hit tool. I like the swing but something Eshleman mentions in his scouting report is the bat can drag in the zone a bit which could lead to issues with higher velocities. In the video, there were a couple instances where he seemed to get jammed as he struggled to get around on inside fastballs. This will cause some issues as he advances against better pitchers with better velocity, so he will need to make some adjustments to be able to continue his performance against better competition.

VERDICT: Cautiously Optimistic

I think there’s a lot to like about Vientos and he’s got youth on his side, will only be 19 going into his 2nd full professional season. I think the power will develop nicely but there are some concerns with the hit tool but I’m going to bet on him figuring it out and being able to a solid big league regular. I plan on targeting him in most of my dynasty leagues.