O’s Starters and the Most Important Counts
There’ an old adage that the first pitch in an at-bat is the most important. The saying suggests that it’s crucial for the pitcher to get ahead in order to see the most success in any given at-bat. Heck, the first pitch strike even has its own Wikipedia page, with the Minnesota Twins prominently featured.
That is great. But wrong. Discuss why in the BSL forums.
There are actually two most important counts in any given at-bat assuming it reaches the given counts. I used the data from this chart at Beyond the Box Score to determine the most important counts for pitchers. That is, the counts where the batters have the largest split in performance should a given pitch be a ball or strike.
Crunching the numbers, and using BA+ as our guide (100 is average, anything above or below is that percentage better than average. E.g. 123 means that batters are 23% better in that count than average) we can see that two counts show the biggest splits.
Batters who see a ball on the 0-1 pitch, resulting in a 1-1 count, have a BA+ of 123. If that second pitch is a strike, resulting in an 0-2 count, batters have an average BA+ of just 61. That is to say that batters in a 1-1 count hit 23% better than average, whereas batters in an 0-2 count hit 39% worse than average. That’s a spread of 62% which is the largest of any split.
Batters who see a ball in a 1-1 count, resulting in 2-1, have an average BA+ of 127 which is 27% better than the average hitter. However, if the pitcher is able to throw a strike the BA+ we would expect to see falls to 66 or 34% worse than average. This results in a spread of 61% which is almost identical to the 0-1 spread.
Now that we’ve established that the 0-1 and 1-1 counts are crucial to the success of a pitcher, let’s consider how that impacts the O’s rotation. I’ll take a look at the 6 key starters the O’s have this year: Chris Tillman, Miguel Gonzalez, Jason Hammel, Wei-Yin Chen, Scott Feldman, and Bud Norris.
For the O’s pitchers I’ll be using wOBA to highlight how significant those counts are. The numbers you’ll see below are the differences between throwing a ball or strike in a given count. The wOBA for all of the pitchers goes down if a strike is thrown, so remember that the numbers shown are how much better hitters perform compared to if the pitcher had throw a strike:
You can see that in every instance the wOBA increases when the pitcher throws a ball versus a strike as you would expect. It is the amount that it changes, more than .100 points for 9 of the 12 instances, that’s interesting. I took all of the 6 pitcher mentioned above and averaged out their wOBA increases to come up with the following figures which I’m using as a proxy for the starting rotation’s performance:
Starting Pitchers (6)
Both counts have seen a .120+ difference in wOBA for batters depending on if the pitcher threw a strike or ball in the given count. That kind of change is huge.
It’s important to challenge what we expect and take a look at how things are really playing out on the field. The next challenge (my next post) will be to break down, more specifically what each of the pitchers do in a given count. I’m less concerned with results, moreso with approach. Remember, the important thing isn’t the result, but the process you go to get the result. The first step is getting the information. My next post will take a look at if the pitchers are following a good process or not.