A few days ago, I shared my list for pitchers from advanced Rookie leagues to High A ball, and this week I'll discuss the AA and AAA lists. This will be the last of my league lists. The final exercise, coming soon, will be a very crude amalgamation of all of the lists, forming a top ~1000 (or whatever number I decide) statistical prospects based on 2018 numbers.
You can read the method for pitchers in the previous article: (LINK). In brief, I use an IP cutoff to qualify pitchers and then calculate their Z-Scores for each league based on Age, K%, Games Started %, BB%, and HR%. I then add up the Z-Scores to get a leaderboard based on the most important inputs that were used in KATOH. BB% and HR% received reduced weight in the lower levels but they get full weight in AA and AAA.
You can see the full leaderboards spreadsheet here: (LINK)
Eastern League
I was shocked to see T.J. Zeuch at #12 on the list. I have, perhaps unfairly, been disregarding Zeuch recently because the low K-rate is such a turn off. I'd even considered omitting him from my own mental Blue Jays top 20 list. The K% was nearly a full standard deviation below my sample mean, but Zeuch more than made up for it by being good at limiting walks and suppressing home runs at a league-appropriate age. Zeuch has always kept the walks and the ball down, and he has a decent minor league history now of also keeping runs down. Zeuch may not be exceeding expectations for a first round pick, but he is probably meeting them and developing fine so far.
Jordan Romano came in at 49th out of 120 arms. The age was the big negative for him, but he also gave up home runs at a rate a bit worse than the sample mean. The mildly positive K and BB rates probably don't help his chances of sticking around in Texas very much.
The Yankees place two prospects in the top 6 that you might not know much about - Trevor Stephan and Michael King. New York's pitching pipeline is enviable.
Peter Lambert was the list-topper. He has a funky wiggle in his delivery but does not have electric stuff, so it will be interesting to see how he translates to MLB.
Texas League
Blue Jays trade acquisition Andrew Sopko did not fare well in his AA sample in 2018 based on this list - he had a negative Z-Score sum. This negative score is due to the lofty HR rate though, all of the other stats were small positives for him. The sample size was small (53.1 IP) and Sopko's A+ numbers ranked well, so I'm not going to overreact to this score.
Jesus Luzardo ran away with the #1 spot in the Texas League and the stats support his case for having legitimate Ace upside. The #2 slot is Parker Dunshee, another Athletics arm who is nothing like Luzardo - it sounds like he might sit under 90 mph and scouts don't appreciate him for more than back-end starter upside. These are always the most interesting players on these statistical leaderboards, the guys who are putting up numbers without the scoutable substrate.
The Astros place five arms in the Texas League top 11 (Cionel Perez, Corbin Martin, Ryan Hartman, Brandon Bielak, and Framber Valdez), which really does not seem fair. Houston had nearly as many high-end statistical performers in AA in 2018 as Toronto did in its entire minor league system. The Astros probably have the best pitching pipeline in Major League Baseball.
Southern League
Brock Burke was the best statistical arm from the Southern League and it's peculiar that the Rays, of all organizations, would deal him after such a standout statistical season.
Kohl Stewart ranking 6th in this league knocked my socks off. I am barefoot. The 4th overall pick in 2013, Stewart limped his way up the Twins ladder with some inconsistent and, frankly, horrendous numbers before 2018. I had completely removed him from my prospect radar but it's really great to see that maybe something finally clicked in 2018.
Dylan Cease, #4 on the list, had a K rate more than THREE! standard deviations above the sample mean. He might have the highest strikeout potential of any starting pitching prospect in baseball right now, considering his stuff and his sublime 2018 results.
Dane Dunning beat his teammate Cease by one spot with a strong statistical profile across the board. If the White Sox can debut Cease and Dunning in 2020, simultaneous with a TJS return from Michael Kopech, they will likely have the most entertaining rotation in baseball.
International League
Sean Reid-Foley edged out Kolby Allard for the #2 spot in the IL. Reid-Foley really earned his big league promotion in 2018 by posting elite AAA numbers. It's encouraging that the K rate was maintained in the bigs, even if the need for some improved command/control was obvious. Toronto has a lot riding on Sean Reid-Foley's development because the organization does not have a whole lot of high-upside SP prospect capital on the immediate horizon.
The #1 IL prospect, Touki Toussaint, barely made the cutoff with just 50.1 IP in the league, but his profile statistically is remarkably similar to Read-Foley's. Both of these players have bat-missing stuff but had BB% figures in AAA that were not assets to their Z-Scores. Both also struggled with walks at the MLB level.
Touki vs. SRF - who ya got?
Jacob Waguespack and Ryan Borucki both rank around 50th in the 135 player sample with mildly positive cumulative scores. Borucki's MLB sample matters more than his AAA one, obviously, but I do worry that his upside-limiting lack of strikeouts will lead to him underperforming vs. fan expectations this season. Borucki is being penciled in as the team's #3 SP, but I think performance closer to the back-end SP variety is more probable.
Pacific Coast League
Trent Thornton made the back of the PCL top 10. He has a history of keeping walks down and the strikeout rate was an asset in the PCL too. It's certainly nice to have him (and Sopko) in the organization considering how thin Toronto's pitching depth seems to be, in my opinion, after putting together all of these lists. SP depth acquisition was/is probably a priority for the Blue Jays and should be viewed as another explanatory angle for the Aledmys Diaz deal.
The PCL #1 Freddy Peralta was more than 2.5 standard deviations better than his league at getting Ks, while being more than a standard deviation worse than the league at giving up free passes. He is a high-variance prospect but certainly a fun one. He will probably be good in one way or another, but I see a lot of shorter outings in his future.
Here is the link again for the full spreadsheet.
Cover Image Source: Joel Dinda on Flickr.
Thanks for reading Stat Scouting the Minors: Z-Scores for Pitchers (AA and AAA) by Nick Hill. If you have any questions or comments relating to this article, we encourage you to leave them below. For all general inquiries, we can be reached at the following:
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