If you’ve been following the Diamondbacks rotation this year, you know it is has been a wasteland of disappointment. Zack Greinke underperformed early, Shelby Miller was one of the worst starters in baseball, and young guys with upside like Patrick Corbin and Robbie Ray haven’t really performed like you would hope.
I want to focus particularly on Robbie Ray today, because he is doing something strange that only a few other starters in baseball seem to do: striking out a lot of batters without a ton of walks, but still carrying a poor ERA and WHIP. Michael Pineda is a popular member of this group. Chris Archer and Jake Odorizzi are two other great examples.
To further illustrate my point, Pineda is 11th in baseball in K%-BB%, Archer is 24th, Odorizzi is 33rd, and our man Ray is 38th. Ray is 19th in K%. Normally, K%-BB% is one of the best in-season predictors of rest-of-season ERA and success. Somehow, in spite of great rates there, Ray has only managed a 4.44 ERA.
Yes, his FIP is 3.99 and his xFIP is 3.71, so his ERA isn’t a realistic view of his current skills anyway, but even his xFIP and FIP are higher than he should have. His 10.2 K/9 makes me think he should be doing better.
Let’s see what’s going on. I’m going to look at my usual favorite stats to figure out if his skills really are much better than his ERA or not.
Well, his BABIP allowed is well above league average, just like his HR/FB%, so he’s been unlucky. On the flip side, that Hard% is not good and it is all backed up by allowing a very high 24% line drive rate, so his BABIP may not be due to bad luck, but lots of good contact allowed. His fastball velocity is still well above average for a lefty, so there are no problems there.
His swinging strike rate overall does a pretty good job of supporting his high strikeout rate and is the 35th highest in baseball. Looking at individual pitches, his slider and four seam fastball both have great swinging strike rates. His two seam is ok and his change-up is awful.
With an awful change-up, you would expect him to struggle against right-handed hitters. Sure enough, here’s his slash line against RHH: 0.295/0.380/0.480. That would be a very good line for a hitter on your fantasy team, but not something you want your pitcher allowing. The funny thing is his strikeout rate is just as good against righties as lefties. His walk rate is worse and his BABIP shoots up to 0.374 against righties.
Other split stats tell the same story: he destroys lefties but can’t get right handed hitters out except through strikeouts. I looked at a bunch of graphs and data to figure out a deeper explanation, but nothing really looks conclusive. Looking at exit velocity, Ray has allowed the 8th most hits with a velocity of 90 mph or more to RHH in baseball.
As you would expect, left-handed pitchers dominate the list with Patrick Corbin, J.A. Happ, Carlos Rodon, Chris Sale (a little surprising), and Dallas Keuchel in front of Ray, among others. Still, 8th most hard hits allowed to righties is not a good place to be. If I limit the list to only hits with that velocity or greater and good launch angles (from 15 to 25 degrees), he is still right there at #7.
What all this tells me is that despite great strikeout stuff, Ray will never be able to maintain an ERA south of 3.7 or so unless he starts to get righties out more. His strikeout stuff is not in question, but his change-up is so bad that he will need elite performance from all his other pitches to stand a chance. Until he improves that change-up (which has a weighted runs above average per 100 pitches of -5.52), he’s going to struggle against righties and that will keep his ERA above where his strikeouts should take it.
If you want some optimism, here you go. Last year, his changeup was much better (1.16 instead of -5.52 in runs above average) and righties only hit 0.244/0.339/0.394 against him. The only difference I can see, unfortunately, between last year's change-up and this year's is that the line drive rate against it went from a fluky-low value of 12.1% to a sky-high 47.8% this year. It is very rare for a pitcher to allow half his hits against a pitch to be line drives, so I don't expect that to stay there all year, but I don't think there is any reason to get excited about his change-up saving him yet.
With an average change-up, I think 3.2 ERAs would be well within his grasp. Sigh. Ray remains just a tease and a streaming starter in nearly all leagues. In deep K/9 leagues, he is probably rosterable, but that’s about it. Tschus!