Brad Radke was drafted 25 years ago. He arrived in 1995 and averaged over 30 starts a year through 2006. The Twins haven't developed a pitcher of his quality since. I wondered about today's better pitchers. What were their numbers in the minors? In particular I wondered about strike outs and walks. Those numbers are relatively fielding independent.

I went to fangraphs as teams were hitting the 81 game point in the season. Starting with 2013 through mid 2016, I sorted the pitchers by fWAR and pulled the top 30. A group of consistently solid pitchers resulted with many top of the rotation pitchers. They range from Clayton Kershaw to Anibal Sanchez. I grabbed the minor league data for the group of pitchers (throwing out anything that appeared to be a rehab stint).

As a group they faced 43897 batters in the minors over 10464 innings. I compared their minor league rates with their major league rates (2013 to mid 2016).

K% (Majors) 23.92%

BB%(Majors) 6.15%

K%(Minors) 23.50%

BB%(Minors 8.78%

The strike out rates in the majors and minors were similar. The walk rates were not. This group of successful pitchers has significantly greater walk rates while pitching in the minors with an increase of more than 40% of 6.15.

Why? Maybe there was some trouble in the low levels of the minors. I compared walk rates at the different levels.

9.32% AAA (3035.1 IP)

8.66% AA (2927.8)

8.15% A+/A (3616.9)

9.08% Short Season (758.1)

The group actually had more trouble with walks in AAA. I also noticed that the group as a whole spent about the same amount of time in AAA as AA. I would have guessed that the better pitchers would have jumped to the majors from AA.

The data wasn't skewed by high walk rates and different levels. I then wondered if individual pitchers having seasons with very high walk rates skewed the data. I looked at individual season/level lines and considered any line with at least 100 batters faced. There were 128 season lines to consider.

There were 39 season/level lines with a rate 10% or greater or a little 30% of the total.

There were 14 lines with a rate of 5% or lower or about 11% of the total.

Overall there were many more season lines where pitchers exhibited significant trouble with walk rates than there were season lines with very good control.

Shouldn't walk rate matter in the minors? Why did so many of baseball's better pitchers struggle with walks in the minors? I wonder if their stuff is so good that they get far fewer outs as a result of weak contact in the minors. Their stuff is so good that a batter (even at AAA) struggles mightily to put the ball in play. The result is deep counts and many more walks. In the majors, some of those swings and misses turn into weak contact and longer counts are avoided.

It seems counter intuitive that a walk would be good. It might be. Maybe when looking at minor league stat lines, the strike out rate and the walk rate should be added. I added the rates and found that the majority (62.5%) of season lines had K+BB% rate of over 30%. There were few season lines (16%) in which the pitcher combined for a K+BB% rate below 25% In all of those plate appearances the batter was not able to put the ball in play. The pitcher's stuff was just too good. Perhaps we should call the K+BB% rate their stuff rate.

What might it mean for an organization? I wonder if some teams see high walk rates and try to fix a problem that really isn't there. In trying to lower the walk rate, they may end up taking away from a pitcher's strengths also. The deep counts as a result of keeping the batter from putting the ball in play is a good thing even if it results in more walks.

How about Brad Radke? He had a very low 5.5% walk rate and a strike out rate of 19% in the minors. Since he retired 10 years ago, the Twins seem to be looking for the next Brad Radke. Maybe that wasn't such a good idea.

The google sheet with the data can be found here.