Putting the Royals MiLB seasons into context with “+” stats

Much has been made of the seasons that a few of KC’s top prospects are having in 2021. Three of the top four HR hitters in all of MiLB this season are Royals prospects. MiLB’s leader in doubles right now is a Royals prospect. Three of the top 13 hitters 23 and younger in all of MiLB are Royals prospects (wRC+). Bobby Witt Jr., Nick Pratto, MJ Melendez, and Vinnie Pasquantino are having certifiably insane seasons right now. Kyle Isbel, Michael Massey, Edward Olivares, Rudy Martin, Tucker Bradley, Emmanuel Rivera, and even Seuly Matias at times have been absolutely fantastic. 30 of the Royals 42 MiLB hitters with 200 PA this season have a wRC+ of at least 101, meaning 71.4% of their prospects have been at least league average hitters in their respective leagues.

The work that Alec Zumwalt and Drew Saylor and company have done to get these guys ready for competition this summer has been nothing short of remarkable. I’ve never seen a turn quite like this from 2019. I think you could make the argument that the hiring of Drew Saylor (the Royals Minor League Hitting Coordinator) in the offseason after 2019 and the cancelled 2020 MiLB season saved some jobs in the Royals front office. It is incredible how quickly they have produced results on the field thanks to a ton of work that went into overhauling the way Royals develop young hitters.

But even with all the success that the Royals hitting prospects are having in 2021, there are certainly reasons for caution in evaluating their performances. I’ve come up with a list of questions and legitimate reasons for caution that I have seen this year in regards to the Royals hitters in the minors:

An overall lack of pitching quality in the minors
Pitchers being behind the hitters after a cancelled 2020 season
Fewer overall MiLB teams and leagues leading to less prepared young talent in full-season leagues
Juiced baseballs
An overall increase in offensive production across MiLB

All of these are totally fair questions and concerns to raise in regard to the 2021 MiLB season. The best response I can come up with off the top of my head is: “Every hitter in MiLB has to face the same pitchers. They’re all using the juiced balls, playing in offensive friendly environments, facing bad pitchers, etc. What ever your concern is, it applies to all of these hitters in MiLB, not just the Royals prospects.”

Still, I understand the concerns, and I think there is merit to them. Here are a few things that I find interesting about how MiLB hitters are translating (or not, rather) to the big leagues in 2021 and how this season compares with past MiLB seasons:

Jarred Kelenic hit .320 with a 0.68 BB/K and 140 wRC+ at AAA this season and is hitting .154 with a 0.33 BB/K and 46 wRC+ for Seattle.
There are 26 hitters aged 25 or younger with an ISO of .250 or better between AA and AAA this season (min. 250 PA). There were 41 in 2019, 13 in 2018, 17 in 2017, and 16 in 2016. So, while there are more this year than ’16, ’17, and ’18, there are actually quite a few fewer “sluggers” than in 2019.
There are 24 hitters aged 23 or younger with at least a 130 wRC+ between AA and AAA this season (min. 250 PA). There were 30 in 2019, 21 in 2018, 30 in 2017, and 34 in 2016. So, really, we’ve seen fewer young guys have significant types of success at the upper levels than we have in the previous four MiLB seasons.

Those obviously are not the end-all be-all points to the discussion. Jarred Kelenic is one of the best young hitting prospects in baseball and I just wanted to point out that despite his success at AAA, we’ve seen a pretty obvious gap between his MiLB performance and MLB performance. Felt semi-noteworthy. The other two points are just that, while there are good points to be made about the overall offensive environments in the minor leagues, there are some things to keep in mind that suggest things aren’t so abnormal as you may think. We’ll find out soon enough, though.

“+” Stats

I use wRC+ all the time at this site. wRC+, in case you aren’t familiar, is a great tool to measure overall offensive production compared to the league a player is in. For example, an .800 OPS in the Low-A East league this year is good for a ~115-125 wRC+. In the Triple-A West, it’s more like 105-115. It’s easier to be a hitter in some leagues than others and wRC+ (weighted Runs Created) gives you a pretty good idea of overall offensive production compared to other hitters in the league. Hitters that are playing in the same parks, using the same balls, facing the same pitchers. The “+” on the end of that stat is what tells you it’s a comparative stat, and can be thrown on the end of anything.

Take OPS, for example. You could say that Mike Trout has a career 1.002 OPS. That’s obviously one of the best marks ever. Way better than Shoeless Joe Jackson’s .940 career OPS. However, when you account for the league’s they played in and the eras, etc., you’ll see Mike Trout’s OPS+ was only 6 points better than Jackson’s. Mike Trout’s career OPS+ is 176, meaning his OPS is 76% better than the league average player during his career. Jackson’s OPS+ is 170, meaning his career OPS was 70% better than the league average player during his career. Despite the 62-point difference in their raw OPS’, the two are only separated by 6 points of OPS+.

Okay, so why does that matter?

I’m going to give you now the ISO+, BB/K+, OPS+, etc. of the Royals prospects compared to their peers in 2021, and then compare those numbers to past MiLB seasons, instead of comparing the raw statistics to past MiLB seasons. Hopefully this will help us weed out the differences in offensive environments, as every hitter in 2021 has the same advantages the Royals prospects do. So… here goes nothing.

The Process

What you’re going to see here is how certain Royals prospects rank in certain statistical categories against everyone in their respective leagues, prospects their own age in their respective leagues, and then how they compare to prospects their age from the same level from past MiLB seasons. I’ll try to explain it more as we keep it moving but it should make sense enough…I think.

AAA (min. 100 PA)

League average OPS at AAA in 2021 is .779
League average OPS at AAA among hitters 23 or younger in 2021 is .803
League average BB/K at AAA in 2021 is 0.472
League average BB/K at AAA among hitters 23 or younger in 2021 is 0.496
League average ISO at AAA in 2021 is .182
League average ISO at AAA among hitters 23 or younger in 2021 is .197

Nick Pratto
– 1.027 OPS
– 0.36 BB/K
– .396 ISO
– 132 OPS+
– 128 OPS+ compared to hitters 23 or younger
– 76 BB/K+
– 73 BB/K+ compared to hitters 23 or younger
– 218 ISO+
– 201 ISO+ compared to hitters 23 or younger

Bobby Witt Jr.
– .970 OPS
– 0.33 BB/K
– .327 ISO
– 125 OPS+
– 121 OPS + compared to hitters 23 or younger
– 70 BB/K+
– 67 BB/K+ compared to hitters 23 or younger
– 180 ISO+
– 166 ISO+ compared to hitters 23 or younger

MJ Melendez
– .973 OPS
– .90 BB/K
– .340 ISO
– 125 OPS+
– 121 OPS+ compared to hitters 23 or younger
– 191 BB/K+
– 182 BB/K+ compared to hitters 23 or younger
– 187 ISO+
– 173 ISO+ compared to hitters 23 or younger

2019 Comparable Players
– Brendan Rodgers (22): 123 OPS+, 111 BB/K+, 131 ISO+; 100 wRC+ in 2021 for Colorado
– Keston Hiura (22): 129 OPS+, 77 BB/K+, 169 ISO+; Struggling in big leagues, K% major issue
– Luis Robert (21): 116 OPS+, 43 BB/K+, 161 ISO+; 120 career wRC+ in big leagues

2018 Comparable Players
– Pete Alonso (23): 122 OPS+, 96 BB/K+, 197 ISO+; 133 career wRC+ in big leagues
– Brandon Lowe (23): 128 OPS+, 107 BB/K+, 178 ISO+; 131 career wRC+ in big leagues
– Mauricio Dubon (23): 119 OPS+, 24 BB/K+, 140 ISO+; 88 career wRC+ in big leagues
– Ryan McMahon (23): 112 OPS+, 56 BB/K+, 146 ISO+; 85 career wRC+ in big leagues

I didn’t want to spend too much time here because we have sort of a limited sample of these guys at AAA so far. We’ll jump to AA next and then try to do both AA and AAA combined to get a full season’s worth after that. I wanted to point out that pretty much all of these guys had their power translate to the big league level. There’s also a pretty good indicator of future success in your BB/K+ numbers. It’s hard to take the swing and miss out of your game, which could specifically be an issue for Nick Pratto who is running up a K% around 30% at the moment in Omaha. He walks a ton and the power seems to be legit, so it could balance out, but it’s certainly something to keep an eye on.

AA (min. 100 PA)

League average OPS at AA in 2021 is .731
League average OPS at AA among hitters 23 or younger in 2021 is .756
League average BB/K at AA in 2021 is .412
League average BB/K at AA among hitters 23 or younger in 2021 is .425
League average ISO at AA in 2021 is .160
League average ISO at AA among hitters 23 or younger in 2021 is .173

Nick Pratto
– .974 OPS
– 0.58 BB/K
– .299 ISO
– 133 OPS+
– 129 OPS+ compared to hitters 23 or younger
– 140 BB/K+
– 135 BB/K+ compared to hitters 23 or younger
– 187 ISO+
– 173 ISO+ compared to hitters 23 or younger

Bobby Witt Jr.
– .939 OPS
– 0.37 BB/K
– .275 ISO
– 128 OPS+
– 124 OPS+ compared to hitters 23 or younger
– 91 BB/K+
– 88 BB/K+ compared to hitters 23 or younger
– 172 ISO+
– 159 ISO+ compared to hitters 23 or younger

MJ Melendez
– .999 OPS
– 0.57 BB/K
– .342 ISO
– 137 OPS+
– 132 OPS+ compared to hitters 23 or younger
– 137 BB/K+
– 133 BB/K+ compared to hitters 23 or younger
– 214 ISO+
– 198 ISO+ compared to hitters 23 or younger

Vinnie Pasquantino
– 1.058 OPS
– 0.85 BB/K
– .265 ISO
– 145 OPS+
– 140 OPS+ compared to hitters 23 or younger
– 206 BB/K+
– 200 BB/K+ compared to hitters 23 or younger
– 165 ISO+
– 153 ISO+ compared to hitters 23 or younger

2019 Comparable Players
– Jo Adell (20): 134 OPS+, 109 BB/K+, 184 ISO+; still getting his feet under him in the big leagues
– Gavin Lux (21): 127 OPS+, 110 BB/K+, 157 ISO+; 79 career wRC+ in big leagues
– Lewin Diaz (22): 119 OPS+, 88 BB/K+, 206 ISO+; still getting his big league career going, showing improvement
– Jazz Chisolm (21): 108 OPS+, 83 BB/K+, 166 ISO+; 105 wRC+ in big leagues in 2021

2018 Comparable Players
– Eloy Jimenez (21): 126 OPS+, 102 BB/K+, 170 ISO+; 124 career wRC+ in big leagues
– Michael Chavis (22): 123 OPS+, 82 BB/K+, 146 ISO+; 83 wRC+ in big leagues, plate discipline major issue
– Brandon Lowe (23): 124 OPS+, 140 BB/K+, 154 ISO+; career 130 wRC+ in big leagues
– Bobby Dalbec (23): 114 OPS+, 29 BB/K+, 179 ISO+; 110 career wRC+ in big leagues
– Brendan Rodgers (21): 114 OPS+, 87 BB/K+, 155 ISO+; 101 wRC+ for Colorado in 2021
– Cedric Mullins (23): 120 OPS+, 118 BB/K+, 141 ISO+; 114 career wRC+ in big leagues

As you can see, the BB/K+ at AA plays a huge role in the amount of success hitters have had in the big leagues. I included a wide range of players in that category to give you an idea of how hitters can turn out if they can maintain their plate discipline into the big leagues. Brandon Lowe would be an outstanding type of outcome for Melendez, Pratto, and Pasquantino. That goes without saying. Brendan Rodgers would be another good type of outcome as he’s still getting his feet under him. We’ve seen what the tools can do for a player like Cedric Mullins, who is likely to finish top 10 in MVP voting this year in the AL. I could go back and look at 2017 too to give you an idea of how this plays out long-term, but with the Royals needing to compete in 2022 and probably make the playoffs in 2023, I wanted to give you an idea of what to expect more in the short-term than long-term. Especially because we’ve seen how quickly young hitters can make massive adjustments into their games.

AA and AAA (min. 200 PA)

League average OPS between AA and AAA in 2021 is .767
League average OPS among hitters 23 or younger between AA and AAA in 2021 is .775
League average BB/K between AA and AAA in 2021 is 0,44
League average BB/K among hitters 23 or younger between AA and AAA in 2021 is 0.44
League average ISO between AA and AAA in 2021 is .175
League average ISO among hitters 23 or younger between AA and AAA in 2021 is .180

Nick Pratto
– .990 OPS
– 0.50 BB/K
– .332 ISO
– 129 OPS+
– 128 OPS+ compared to hitters 23 or younger
– 114 BB/K+
– 113 BB/K+ compared to hitters 23 or younger
– 190 ISO+
– 185 ISO+ compared to hitters 23 or younger

Bobby Witt Jr.
– .945 OPS
– 0.36 BB/K
– .293 ISO
– 123 OPS+
– 122 OPS+ compared to hitters 23 or younger
– 81 BB/K+
– 81 BB/K+ compared to hitters 23 or younger
– 168 ISO+
– 163 ISO+ compared to hitters 23 or younger

MJ Melendez
– .987 OPS
– 0.59 BB/K
– .337 ISO
– 129 OPS+
– 127 OPS+ compared to hitters 23 or younger
– 134 BB/K+
– 134 BB/K+ compared to hitters 23 or younger
– 193 ISO+
– 187 ISO+ compared to hitters 23 or younger

2019 Comparable Players
– Luis Robert (21): 125 OPS+, 50 BB/K+, 177 ISO+; 125 career wRC+ in big leagues
– Kyle Tucker (22): 123 OPS+, 117 BB/K+, 192 ISO+; 121 career wRC+ in big leagues
– Franklin Barreto (23): 125 OPS+, 84 BB/K+, 171 ISO+; K% major issue in big leagues
– Keston Hiura (22): 147 OPS+, 82 BB/K+, 234 ISO+; K% major issue in big leagues
– Dylan Carlson (20): 124 OPS+, 113 BB/K+, 165 ISO+; 102 career wRC+ in big leagues
– Luis Urias (22): 135 OPS+, 132 BB/K+, 189 ISO+; 108 wRC+ for Milwaukee in 2021

2018 Comparable Players
– Eloy Jimenez (21): 129 OPS+, 105 BB/K+, 161 ISO+; 124 career wRC+ in big leagues
– Brandon Lowe (23): 128 OPS+, 127 BB/K+, 175 ISO+; 130 career wRC+ in big leagues
– Austin Riley (21): 118 OPS+, 63 BB/K+, 149 ISO+; 115 career wRC+ in big leagues
– Tyler O’Neill (23): 145 OPS+, 97 BB/K+, 256 ISO+; 129 wRC+ for St. Louis in 2021
– Sean Murphy (23): 115 OPS+, 120 BB/K+, 137 ISO+; 115 career wRC+ in big leagues
– Ty France (23): 110 OPS+, 117 BB/K+, 132 ISO+; 118 career wRC+ in big leagues

2017 Comparable Players
– Ryan McMahon (22): 132 OPS+, 99 BB/K+, 156 ISO+; 94 wRC+ for Colorado in 2021
– Lewis Brinson (23): 129 OPS+, 115 BB/K+, 158 ISO+; just now figuring things out at 27
– Matt Olson (23): 125 OPS+, 120 BB/K+, 203 ISO+; 132 career wRC+ in big leagues
– Derek Fisher (23): 129 OPS+, 105 BB/K+, 182 ISO+; 79 career wRC+ in big leagues
– Kyle Tucker (20): 112 OPS+, 76 BB/K+, 170 ISO+; 121 career wRC+ in big leagues
– Rafael Devers (20): 128 OPS+, 120 BB/K+, 183 ISO+; 120 career wRC+ in big leagues
– Austin Riley (20): 120 OPS+, 89 BB/K+, 135 ISO+; 115 career wRC+ in big leagues

Takeaways

MJ Melendez’ power is legit. I don’t care what year you throw him into comparisons for. His 187 ISO+ compared to prospects his age is the 13th best mark over the last four MiLB seasons. His BB/K+ compared with that group is in fantastic shape. Yes, the overall offensive environments in the upper minors has absolutely exploded over the last couple of MiLB seasons, but Melendez compares favorably to any power hitter in any year. The work he’s done to come back from a miserable 2019 showing in Wilmington is nothing short of miraculous. What a job he’s done to resurrect himself at the plate to become a legitimate force offensively at a premium position.

Brandon Lowe kept popping up as comparable player for our group of 3-4 Royals prospects. If any of those four turn out like Brandon Lowe at the big league level, Lord have mercy. Lowe has a career .250/.339/.506/.845 slash line, has 30 HR this season for Tampa Bay, and a career 130 wRC+. Imagine getting that kind of offensive output from your everyday catcher (yes, that was sort of a Salvy pun). You’d sure as hell take that from Vinnie Pasquantino, whose numbers most closely align with Lowe as a prospect. Vinnie is gonna play 1B or DH, where Lowe still draws some value playing 2B for Tampa Bay, but you’ll take that offensive production every day of the week from an 11th round draft pick out of Old Dominion. Pratto and Witt Jr. would also be good enough defenders to make that offensive production All-Star caliber.

There are a ton of names and numbers on this list, but here are a few of the most important things to take away from the article:

It’s going to be really important for Bobby Witt Jr. and Nick Pratto to cut down on the strikeouts at the big league level. Pratto is striking out in 30.6% of his PA at AAA at the moment, and while I thought his K% issues were approach oriented in AA, he is swinging and missing a ton in Omaha. He’s also hitting for mammoth amounts of power, so it’s sort of evened out, but the power won’t matter as much in the big leagues if he can’t make contact with big league pitching. Bobby’s K% is basically identical to his AA mark, but he’s just so aggressive. A hitter with his ability is going to get walked naturally. Pitchers don’t want to get continually beaten into the dirt. They WILL walk him if he lets them. Sometimes he gets so swing happy he ends up chasing bad pitches and getting himself in less advantageous counts. The number one predictor of big power guys busting in the Show is a high K%. It’s obviously still very manageable to succeed with a low BB/K (see: Perez, Salvador), it’s just easier when you’re willing to take a walk once in a while.
Almost everyone on this list that was 22 or younger has had some success in the Show. It’s harder to judge when the hitters are 23 still playing in AA, but Pasquantino’s “+” stats are so elite that he’s among the very best. Can he keep hitting as he keeps moving? I don’t see any reason why not. He’s going to have to hit a ton to be super valuable but we’ve seen plenty of evidence that he’ll do just that. His splits against LHP will help him as well, as he really doesn’t lose a ton against southpaws.
Bobby Witt Jr. and MJ Melendez are among the only borderline ++ defenders on these lists. Sean Murphy and Lewis Brinson are great, but that’s about it. Otherwise you’re looking at a ton of bat-first, corner outfield and 1B types. Add in a potentially Gold Glove-caliber defender and you’re legitimately looking down two of the highest ceiling prospects in all of Minor League Baseball.

Top Prospects Who Were Not Mentioned

Really quickly, here’s a quick comparison of Melendez to Rutschman and Bart, Witt Jr. to Jose Rodriguez and Spencer Torkelson, and Pratto + Pasquantino to Triston Casas and Spencer Torkelson.

Catchers
– Melendez (AA/AAA): .987 OPS, 0.59 BB/K, .337 ISO
– Rutschman (AA/AAA): .907 OPS, 0.90 BB/K, .218 ISO
– Bart (AAA): .906 OPS, 0.26 BB/K, .214 ISO

Hitters
– Witt Jr. (AA/AAA): .945 OPS, 0.36 BB/K, .293 ISO
– Rodriguez (A+/AA): .973 OPS, 0.67 BB/K, .212 ISO
– Torkelson (AA/AAA): .878 OPS, 0.57 BB/K, .278 ISO

First Base
– Pratto (AA/AAA): .990 OPS, 0.50 BB/K, .332 ISO
– Pasquantino (AA): 1.044 OPS, 0.89 BB/K, .248 ISO
– Casas (AA): .785 OPS, 0.67 BB/K, .145 ISO
– Torkelson (AA/AAA): .878 OPS, 0.57 BB/K, .278 ISO

So, again, say what you want about offensive environments, but it’s the same offensive environments for everyone and the Royals top prospects are kicking ass no matter how you look at it.