I was reading through some of the material on Fangraphs that explains the Pitch/FX charts, and in one of them, they picked Mike Minor to use as an example. A comment in the article, written last year, mentioned Minor's "unusually low home run rate." Erm...
As we all know, Minor has been one of the worst starters in the NL in giving up home runs in 2012, and overall, his pitching has been below league average. He's currently carrying an ERA of 6.20 and a Fangraphs WAR of -0.4. His walk rate is up, and opposing batters are slugging an alarming .498 off of him, despite a BABIP of only .287.
So what has changed for Minor from last year to this year? Looking at some Pitch/FX charts from Fangraphs, the big thing that jumps out is loss of command. Below are the Fangraphs horizontal and vertical movement charts from 2011 (left) and 2012 (right):
Blue = fastball, green = changeup, red = slider, and purple = curve. The immediately obvious thing is that all of the clouds, except maybe the changeup, look more spread in the 2012 chart, suggesting loss of command. The curveball is mainly spread in the horizontal, while the others are spread in both the horizontal and vertical. The changeup in particular seems to have a lot more outliers, although some of those may actually be fastballs that were mis-classified by Pitch/FX's system. This heat map, of fastballs thrown to righthanders in the two seasons, further illustrates the problem:
(I didn't show the map against lefthanders because Minor hasn't pitched to enough lefthanders this year to make a good sample size, and righthanders are statistically what he has more trouble with.) Location is not great in either season, but at least in 2011 he kept most of the fastballs down in the lower half of the strike zone. In the 2012 map, he seems to have no idea where it's going.
Looking at the weighted Pitch/FX pitch values from Fangraphs, we find the following changes from last year to this year:
- Fastball went from -0.08 to -0.54
- Slider (which he only started throwing last year) went from -1.90 ro -2.41
- Curveball went from -1.82 to +0.29
- Changeup went from +1.15 to -1.45
Minor's fastball was never a great pitch, but the lack of location has made it worse. I didn't show the slider heat maps, but they show the same phenomenon. A story that has been hidden this year is Minor's curve going from a pretty bad pitch to a plus pitch. I'm guessing this has to do with better vertical movement, as shown by the scatter charts. The more random horizontal movement in the 2012 cloud may actually be an advantage for that pitch, providing a sort of knuckleball effect -- the batter can't tell what it's going to do.
The real puzzler here is the changeup, going from a good plus pitch to a bad pitch. Why is that happening? Looking at numbers and scatter charts, nothing obvious is jumping out. Velocity is down a bit from last year (as it is for all of Minor's pitches), but that shouldn't hurt a changeup. Minor's changeup is unusual in that it has a bit of a screwball action, meaning that it breaks away from right-handed hitters. I see that Minor tends to throw it inside to righthanders, which maybe gives them too good of a look at it. But he did that last year too. So it could be a matter of scouting and hitters adjusting to it. Although there's another possibility, which I'll discuss in a moment.
The other thing I've noticed about Minor's pitching this year is that he has gone to a more over-the-top arm angle. The Pitch/FX release point charts bear this out; they show a release point that's higher and closer to the body centerline. This may have been an adjustment made to improve the curve ball, and if so it worked, but at the cost of reducing Minor's command over the fastball and the slider. As a general rule, pitch location error occurs in the plane of the arm motion; it's easier to keep the ball down with a lower arm angle because more of the location error will be in the horizontal plane. Minor's going to a more vertical arm angle makes it easier to get more vertical motion on the curve, but it results in more fastballs and sliders being left up. It doesn't seem to have had a direct effect on the changeup, but I wonder about something else: Minor is a pretty tall guy with lanky arms, and in general, a higher release point is easier for the batter to see. This makes me wonder if the problem with the changeup is that Minor is tipping it somehow, and the change in arm angle has made the tip more visible. (Or maybe it just took this long for the info to get around the league...) Any time a certain pitch goes from being a great pitch for that pitcher to being a terrible pitch, and nothing seems to be different about the pitch itself, you start to wonder about tipping.
An oddity in Minor's stats is that the difference between his batting-average-against and his BABIP is only 18 points. This means that nearly every time a batter hits a fair ball against Minor, they get a hit. Minor's ground ball rate is down significantly from last year. His line drive rate is also down, interestingly, but both his home run rate and his infield fly rate are up. This is what you might expect for a pitcher who is throwing a lot of fat pitches; either a hitter gets it and a long fly ball results, or he misses it and the result is a pop-up.
- The higher arm angle is not working, despite the improvement in the curve ball. Drop it back down.
- Scrap the slider, at least for this year. Maybe work it on winter ball. Or maybe Minor should get Jonny Venters to teach him a sinker. Or maybe don't bother. If Minor can keep throwing the good curve ball, and figure out what's going on with his changeup, those two pitches and a halfway decent fastball would be enough for a good 3-4-5 starter.
- Part of the problem appears to be mental. Minor is actually pitching decently at home, at least replacement level. On the road, his slash line against is .280/.357/.572(!). In away games, he's allowed 56 hits in 50 innings, which is not terrible, but... 24 of those hits, about 1 out of 2, went for extra bases. Look at the batting average vs. the slugging... .280 doubled is .560. So on average, every hit against Minor on the road is a double. If Minor were really that bad a pitcher, he would never have made it past AA ball. Maybe he needs to hunt up John Smoltz's sports psychologist.
- Have some of the Braves' hitters take a good close look of Minor throwing his changeup last year and this year. See if they can spot anything that might tip the pitch.