On Monday we looked at the hitters in the draft classes from 2008 to 2014 and broke it down to compare how the drafts under Ed Wade performed versus the ones under Jeff Luhnow.
Now, we'll take a look at the pitchers. The method is the exact same. We will compare the pitchers using the same idea of using BB/SO ratios. Instead of batting average and on-base percentage, we'll use ERA.
Under Wade, your typical pitcher draftee was usually quite athletic and projectable. Scouting side of things again reigned supreme. They looked at what pitchers could potentially become. Athletic guys could gain an ability to repeat their delivery and improve control/command. Pitchers who haven't quite filled out their frame would gain strength and velocity leading to better strikeouts.
Luhnow has leaned toward collegiate arms with a track record of limiting walks, weak contact, and throwing strikes. Quite a different philosophy. The BB/SO ratios shown here will likely quantify that difference and we'll see if it has an effect on professional performance via ERA.
The BB/SO ratio under Luhnow is .085 lower which is pretty significant and indicates either a lower walk rate or higher strikeout rate. And in this case, it's both. The pitchers under Luhnow have exhibited better control overall. They've also shown a knack to miss bats as well due to a much improved strikeout rate.
Overall, it appears that the better control of the strike zone has a significant improvement in the pitchers performance as the ERA is over half a run lower. Now, there are other factors at play such as the batted ball profile. So, we can't say definitively that the improved BB/SO ratio is the reason for improvement. However, research has shown that better BB/SO ratios do have impact on performance. So it is reasonable to conclude that.
The highest ERA and BB/SO in the Luhnow drafts are still better than the lowest ones that any of Wade's drafts did.
Now lets look at the success rates by totaling how many topped out in A ball or lower.
That's a total of 46% of the pitchers drafted under Ed Wade topped out in A ball or lower.
Under Luhnow, 58% have so far topped out in A ball or lower. But when you factor that 100% of 2014 draft is still there, as they should be, that makes sense. Lets say half of the 2014 class makes it to High-A before it's all said and done (which is reasonable) then the total of Luhnow's drafts drops to 42%. That's lower than Wade's.
Just like with the hitters, the BB/SO ratio's have shown a trend to improved performance in the minors and expectancy for continued improvement in quality of the Astros farm system.