Micro-Brew: Mitch Stetter’s fastball optional?

There are so many topics we could discuss about the Brewers latest flop, but the one alas there is only so much time.
So lets take a look at where the game got out-of-hand: Mitch Stetter‘s appearance.
Replacing Dave Bush in the 7th inning, Stetter retired Nate McLouth on a fly ball before allowing three straight singles, allowing one run to score on his watch, and having Todd Coffey allow his inherited runners to score as well.
The game went from a tight 3-1 ballgame to 6-1, dropping the Brewers win expectancy from 20 percent to about four.
Let’s first take a look at Stetter’s pitch chart (click to advance to his PitchFX page for the game):

Now, this is from the catcher’s perspective, and three of the four batters that Stetter faced were lefty (Nate McLouth, Jason Heyward and Brian McCann), which explains the high percentage of pitches that would be low-and-away to a left-handed batter. Martin Prado, the lone righty, saw that “true” ball on the outside corner and the fat mistake pitch that was hit for the first single (light blue and in a righties’ wheelhouse).
What is most interesting about this chart though? Stetter threw 15 pitches, and according to PitchFX a whopping 14 (yes, FOURTEEN) were sliders.
Now, when I was growing up and playing little league baseball, I often read books about how to play and how to throw certain pitches. I remember just about every one read that a pitcher should throw his fastball about 60-80 percent of the time, using change-ups and other pitches to compliment it.
Now, of course I don’t expect MLB-caliber pitchers to follow such an approach, unless they are of the Billy Wagner or Joel Zumaya approach. Some pitchers best pitch just isn’t their fastball.
This includes Mitch Stetter, who’s slider is about 17 runs above average over his career, while his fastball is about six runs below average, largely because he throws it in the mid 80s.
However, to go out and not even really attempt to work in a fastball, seems a little silly to me unless you are Tim Wakefield.
A fastball is tough to hit because it require very quick recognition and maximum reaction speed. And pitches like the slider are inherently more effective because of the threat of the fastball.
How many times have we seen a player take a called third strike on a hittable heater, because they were sitting on another pitch? If you don’t recognize a fastball immediately, hitting it is pretty tough. However, we all know that MLB hitters can hit just about anything (maybe not a knuckleball) pretty consistently if they know its coming. It’s why 3-1 fastballs are about the most hit pitches in the game.
According to PitchFX, Stetter threw his one fastball to Prado, though looking closely at the pitches leaves reason to wonder if he actually threw two fastballs to him, as all of his sliders are within a couple MPH of 78.83, except for his 2nd pitch to Prado which was at 85 MPH. I think it was probably just a really live fastball that was miscategorized, or maybe some sorta mystery pitch (according to FanGraph’s a whopping 62.5 percent of his pitches this season can qualify as unknown).
But what this really means is that against the three left-handed hitters he came into face, he threw 13 pitches and 13 sliders.
As good as that slider is, Heyward and McCann surely had picked up on Stetter’s act by the time they came up, having seen him throw five sliders to McLouth to open the inning.
Over his career, Stetter has thrown his fastball 42.4 percent of the time. So why he opted to essentially shelve it on Tuesday is a mystery. Maybe he couldn’t control it in the bullpen. Maybe those particular Braves lefties can’t hit sliders (totally doubt that).
But I think if Stetter wants to stick with the club as a guy who can get lefties out, he better reconsider using it a little more often, or risk more outings like Tuesday.
Until next time, Sláinte!