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Success rates for Double-A League prospects based on walk and strikeout rates

Using historical prospect lists, which current prospects have helped their chances at Major League success based on their walks, strikeouts, and age?

Greg M. Cooper-USA TODAY Sports

Introduction

This is the third and final time I will look at historical walk and strikeout rates for prospects. If you followed my previous installments, much of this will look familiar to you; however, these results are more complex and different. For those who are new, the basic premise is this: how likely is it that an offensive prospect succeeds in the major leagues based only on his minor league walk and strikeout rates?

Previous Levels: Rookie | Short-A | Single-A | Advanced-A

Method

First, I compiled the minor league numbers for all Baseball America top 100 offensive prospects from 1990 to 2007. I stopped at this year to allow enough time for the player to achieve MLB success. I only include top 100 prospects to add in a form of scouting to the picture. Stats and scouting should work hand-in-hand and an analysis similar to this can help augment a scout’s evaluation of talent. Next, I compared each prospect’s walk and strikeout rate to the league average that year, creating BB+ and K+ metrics. Finally, I compared the walk and strikeout rates at various ages and levels of prospects in the minor leagues to their career MLB Fangraphs Batting runs. Batting runs are calculated using the wOBA linear weights and adjusting for park effects. Basically, how many total runs above average did the player produce on offense, after adjusting for park.

In order to put players into the low, average, and high categories for BBs and Ks, I use a 15% variation from 100 BB+ or K+. This means that 85-115 marks average for each, while players below 85 are "Low" and players above 115 are "High." Since this analysis relies on bins, I allow for a 5% variation on the cutoffs. For instance, if a player has an 83 BB+ (78-88), I look at the historical percentages for both low and average walk rates.

Prospects are required to have 150 PAs at a level to qualify in this analysis.

The following table is an estimate of where these cutoffs actually lie in terms of BB% and K% values.

BB% K%
Low 7.7% 15.4%
High 10.5% 20.8%

A player with at least 0.01 Batting runs in 1500 career plate appearances is tagged "Productive," while players with negative batting runs or fewer than 1500 career PAs are "Busts." It is important to note that I am only interested in hitting ability. This is how Edgar Renteria ends up in the "Bust" category. He had a great career, accumulating 35.7 fWAR; however, his batting was worth -52.3 runs.

Results

Here are the historical results for prospects in High A, split by BB%, K%, and age.

Prospectpercentaa

Double-A is the prospect’s first real taste of upper level baseball. It is a league of separation where a bad approach or hole can be exploited by better pitching. The best chance at becoming a productive hitter comes from a high BB/low K approach. High K hitters have much lower chances of succeeding, unless their BB rate is also high. Older players with a low walk rate are in dangerous territory as well, even if their strikeout rate isn't bad.

Here is an overall success table for this level, based solely on age.

Prospectoverallaa

The magic age for prospects in Double-A is 21. Over 28% of prospects 21 and younger in AA became successful hitters, while only 12% of those 22 or older did so. Of those older prospects that became productive, their approach generally included either a low K rate or a high BB/ high K rate. It is interesting that an above average amount of older players in AA with a High/High approach became productive. This includes players such as Tim Salmon, Ryan Howard, Jason Bay, and Pat Burrell.

Prospects in 2013

How do 2013 preseasons consensus top 190 prospects and select draft picks that played in Double-A this year stack up in this analysis?

Name Team 2013 Rank BB+ SO+ Prod% Avg% Bust%
Xander Bogaerts Red Sox 9 153 99 78% 0% 22%
Gregory Polanco Pirates 54 142 64 56% 13% 31%
Taylor Lindsey Angels NA 96 81 39% 6% 55%
Edward Salcedo Braves 181 96 108 36% 4% 60%
Jose Ramirez Indians NA 83 39 30% 17% 52%
Eddie Rosario Twins 119 76 108 28% 0% 72%
Maikel Franco Phillies 141 39 54 27% 18% 55%
Tyler Austin Yankees 82 127 109 27% 9% 64%
Cheslor Cuthbert Royals 169 86 98 27% 19% 54%
Brian Goodwin Nationals 58 140 115 26% 13% 61%
Miguel Sano Twins 15 147 148 25% 8% 67%
Randal Grichuk Angels NA 58 86 24% 3% 74%
Kaleb Cowart Angels 48 79 115 24% 0% 76%
Alen Hanson Pirates 52 60 87 24% 22% 54%
Marcus Semien White Sox NA 197 69 23% 31% 46%
J.R. Murphy Yankees NA 129 77 23% 31% 46%
Stephen Piscotty Cardinals NA 104 46 22% 17% 61%
Garin Cecchini Red Sox 133 195 89 22% 22% 56%
Max Muncy Athletics NA 138 87 22% 22% 56%
Christian Yelich Marlins 11 132 118 21% 8% 70%
Joc Pederson Dodgers 121 152 111 21% 8% 70%
Arismendy Alcantara Cubs NA 123 110 21% 8% 70%
George Springer Astros 46 147 150 21% 16% 63%
Chris Taylor Mariners NA 151 93 20% 13% 67%
Christian Bethancourt Braves 117 47 74 20% 5% 75%
Ronny Rodriguez Indians 157 36 77 20% 5% 75%
Anthony Rendon Nationals 26 223 83 20% 9% 71%
Brad Miller Mariners 136 129 87 20% 9% 71%
Trayce Thompson White Sox 145 115 119 18% 10% 72%
Kyle Parker Rockies 152 86 95 17% 11% 72%
Josmil Pinto Twins NA 160 79 17% 17% 67%
Thomas La Stella Braves NA 129 53 17% 17% 67%
Reymond Fuentes Padres NA 115 89 16% 18% 66%
Yasiel Puig Dodgers 73 102 88 16% 11% 74%
Jacob Realmuto Marlins 146 98 83 16% 11% 74%
Henry Urrutia Orioles NA 121 81 14% 14% 72%
Max Stassi Astros NA 66 106 11% 5% 84%
Orlando Calixte Royals NA 89 123 10% 4% 86%
Slade Heathcott Yankees 85 92 122 9% 9% 82%
Jake Marisnick Marlins 63 64 115 5% 10% 84%
Robert Hefflinger Braves NA 82 156 5% 0% 95%
Julio Morban Mariners NA 97 147 0% 8% 92%
Javier Baez Cubs 18 91 143 0% 0% 100%
Roman Hernandez Royals NA 87 111 0% 0% 100%
Yorman Rodriguez Reds NA 98 133 0% 0% 100%
Kevin Pillar Blue Jays NA 66 48 0% 0% 100%
Domingo Santana Astros NA 109 147 0% 0% 100%

Baez sticks out here as an elite prospect with a low projected success rate and I wrote about him in the Advanced-A post. Another player of note is Yasiel Puig. As a 22-year old in Double-A, he was a little old for a prospect in that level, meaning only a great approach would give him a high percentage of success. He almost accomplished that, with a fairly low K rate. However, it was just a smidge too high and dropped his Prod% by six. Also, he was a Cuban signing this past offseason, meaning he did not have the typical prospect career path.

Bogaerts and Polanco are two of the top prospects in baseball, and this helps show why. Not only do they have heaps of talent, but they also have great approaches to go with it. Bogaerts didn’t quite dominate in AAA like he did in AA, but he still had a great showing. He should be in the Red Sox starting lineup in 2014 and for years to come. Polanco helped himself in AA after not walking enough in Advanced-A. If he keeps that up, he’ll be in Pittsburgh by late 2014 or early 2015, depending on the Pirates’ needs.

Springer is a divisive prospect, due mainly to his huge amounts of strikeouts. Not many (if any) doubt his combination of power and speed, but just as many are skeptical he will make enough contact to do damage in the majors. This system has him pegged at right about average in terms of likelihood of boom or bust, thanks to his ability to take a walk. He spent enough time in AAA to qualify and helped himself even more there. As long as he can take a walk at well above the league average--and nothing points to his inability to do so--Springer will be able to get on base and into enough hitters' counts to become productive.

The Angels have several prospects near the top, including Lindsey, Grichuk, and Cowart. Grichuk was traded to the Cardinals in the Peter Bourjos deal, giving the Cardinals another prospect with a good approach along with Piscotty. Cowart had a down year overall, but it appears that his approach did not suffer too greatly, and that may help improve his stock next year.

Conclusion

Double-A is the transitional level, where prospects must turn their dreamy tools into actual performance. If a player has not learned how to take a walk by now, they probably never will and their chances of becoming a productive hitter are slim to none.

Which other players in Double-A caught your eye this year?

. . .

Statistics courtesy of Fangraphs and Baseball Prospectus.

Chris St. John is a writer at Beyond The Box Score. You can follow him on Twitter at @stealofhome.