By Chris St. John
A few months ago, I created a database that includes all of the prospect rankings from Baseball America, Keith Law and Kevin Goldstein. I didn't have a direct purpose for it, I'm just the type of person who likes to accumulate as much data as possible. So it sat around on my computer until I found a good use for it. Well, thanks to fantasy baseball and Starling Marte's horrible 3.8% walk rate in AA last season, I have. Marte is a possible target in my dynasty minor league draft and I wanted to see what other prospects had poor walk rates and how successful they were in their careers.
In interest of saving digital space (and your scrolling finger), I will only post the full method on the Rookie and Low-A edition of this series.
Rookie and Low-A
350 of the 480 prospects in this dataset accumulated at least 150 plate appearances in Single-A. 19% were successful, 20% were average and 61% were busts. This is close to the overall 21/21/58 trend for all prospects.
No single prospect with a low Advanced-A walk rate turned into a productive MLB hitter. Nearly three quarters of them were busts. Players with high walk rates had a bust percentage of only 48%.
Correlation to MLB
This graph shows the correlation between Advanced-A walk rates and MLB walk rates.
High Walk Rate: Derek Norris, Brandon Belt, Josh Fields, Tyler Flowers, Joey Votto, Lars Anderson, Steve Pearce, Taylor Teagarden, Mat Gamel, Jose Tabata, Trevor Crowe
Low Walk Rate: Christian Bethancourt, Hector Gomez, Starling Marte, Chris Owings, Matt Szczur, Angel Villalona, Neil Walker, Peter Bourjos, Alcides Escobar, Cesar Puello
All five players with very high strikeout rates were busts (Hensley Meulens, J.R. Phillips, J.J. Davis, Al Shirley and Earl Cunningham). The success rate of prospects with high or very high strikeout rates is nearly double in Advanced-A (14%) than Single-A (7.5%) It does appear that high strikeout players are more likely to be boom/bust types, since 91% of these players fit into one of those categories.
The two prospects with very low strikeout rates were Jason Kendall (Average) and Mike Caruso (Bust). The six productive hitters with high strikeout rates were Manny Ramirez, Jack Cust, Ryan Howard, Juan Gonzalez, Russell Branyan and Josh Phelps.
High Strikeout Rate: Jared Mitchell, Chris Davis, Jonathan Villar, Trayvon Robinson, Greg Halman, Wladimir Balentien, Chris Carter, Billy Rowell, Matt Davidson, Joey Votto, James Jones, Justin Upton
Low Strikeout Rate: Ben Revere, Daric Barton, Andrelton Simmons, Cedric Hunter, Chin-Lung Hu, Nolan Arenado, Hector Gomez, Erick Aybar, Julio Borbon, Brandon Belt, Jacoby Ellsbury, Domonic Brown, Starlin Castro
Correlation to MLB
This graph shows the correlation between Advanced-A strikeout rates and MLB strikeout rates.
Strikeout to Walk Ratio
Finally, this plot shows the relationship between Advanced-A K/BB and Major League Batting Runs per Plate Appearance:
The correlation between Advanced-A and MLB strikeout rates is much higher than for walk rates, meaning a player is much more likely to stay a high-strikeout player at all levels. A player with a low walk rate is much less likely to succeed in the big leagues. These two are probably related. If it is possible for a player to succeed while striking out a ton, there is no reason for him to improve in that area.
If you would like to know anything specific about the data, you can contact me in the comments section below or on Twitter @stealofhome.