How Did Wade Miley Get So Good?

Wade Miley wasn't even supposed to be on the roster, only making it in on the very last day, after Takashi Saito went on the disabled list. And then, Miley wasn't supposed to be in the rotation, stepping up to fill in after Josh Collmenter floundered in his first three outings. He certainly wasn't supposed to be this good. Sure, he'd done decently as a fill-in at the back-end of last season, posting a 4.50 ERA in seven starts and 40 innings. But at the time of his call-up last August, John Sickels said, "Miley projects as a number four starter, or perhaps a number three if everything develops perfectly."

Yet here we are, in late June, and Wade Miley is the consensus pick to represent the Diamondbacks at the All-Star Game. That's the result of a 2.30 ERA, fifth-best in the National League over 11 starts and 82.1 innings of work. What happened?

It's a fair question. After all, between Mobile and Reno in the minors last season, Miley's ERA was 4.30, which is hardly the stuff of top prospects. Even after his decent appearances in the major league, Sickels still ranked Miley only #13 in January, repeating his back of the rotation projection, but adding, "He needs to [develop] right now or he'll get buried by guys with higher ceilings." Thomas Belmost of Baseball Instinct concurred the following month, but put Miley even lower, at #17: "He’s not going to pile up strikeouts so his upside is a back end of the rotation starter." Why didn't they see this coming?

The most obvious difference is much, much better control. In the minors, he walked 3.1 batters per nine innings; in his first major-league stint, that number went up to 4.1. But so far in 2012, that rate is all the way down to 1.9, with 17 walks in those 82.1 innings. And of late, his control has been near-impeccable: Miley has issued one walk in June, over four starts [unfortunately, that runner came round to score in the 1-0 loss to Texas]. He has been seriously attacking the strike-zone, throwing 71% of all pitches for strikes in that time, significantly above the 63% MLB average. The result? A 2.10 ERA, with seven earned runs allowed, and 25 strikeouts in 30 innings of work.

The pundits were correct, however, in that Miley has not generally piled up a lot of K's. His overall rate this year is 6.6 per nine innings, compared to the National League average for a starter this year of 7.3. That's about in line with Miley's minor-league number of 7.0, though considerably lower than what he did with the Aces in 2011, when he struck out fractionally more than a batter per inning. The breakdown of his strikes, e.g. looking vs. swinging isn't far off normal. There's a bit more contact (82% vs. 79%) when hitters swing, but he also gets a few more strikeouts looking than most (28% vs. 24%).

Wade is throwing the ball harder this year. His average fastball is up to 91.1 mph from 90.3 in 2011, but the difference is particularly noticeable with regard to his slider, which has gone from 78.7 mph to 81.0. Both have also become more commonly-used parts of his arsenal. Last year, about three out of every four pitches Miley threw were fastball or slider, with the rest mostly change-ups, and the very occasional (4.6%) curveball, just to keep hitters honest. This year, almost 85% of pitches are fastball/slider, with a sharp decrease in change-up, and the already rare curveball is almost gone, thrown just 2.6% of the time.

[As an aside, I note the sharp distinction in pitch classifications on his page at Fangraphs between the numbers shown under 'Pitch Type' and 'pitch f/X Pitch Type'. The latter seems to all but deny the existence of Miley's slider - looks like that system calls it a curve-ball. That doesn't quite gibe with the evidence of my eyes, having seen a good number of batters hacking wildly at Miley's version of "Mr. Snappy," as Randy Johnson called his infamous out pitch. Looks like a slider to me, so that's why I'm going with the Pitch Type numbers.]

Miley recently told the Republic that, of all people, Paul Goldschmidt might bear some responsibility for his recent success: "We carpool a lot and were driving to the park a little while back and he said, 'Man, you used to throw your slider a lot harder back in college.' That got me thinking and so I started experimenting with throwing it as hard as I can. I was able to feel it and throw it for strikes and I've just kind of ran with it." [As an aside, read the article also to learn about the team game Words With Miley, where Miley has to spell obscure words and use them in a sentence - one of the examples given is "schadenfreude." Hmm....]

It was interesting to listen to Tom Candiotti cover Miley's start on Monday [I think when it comes to analyzing pitchers, he's probably better than Mark Grace, for obvious reasons]. Candiotti was absolutely enamored of Miley's ability to 'hide the ball' during his delivery action. It's the first time I've heard this aspect of his game being described to such a degree, and if this is a relatively recent adjustment, it could explain both the success and uptick in strikeout rates we've seen this month.

As an aside, got to mention Miley's ability to help himself at the plate, having gone 10-for-26 with two doubles - that's a .385 average. Ok, a BABIP of .500 is probably not going to be something he can keep up. But only 15 pitchers in all last season had more hits, than Miley has managed in barely a third of one. Might be as much a flaw in fWAR as anything, but on offense, our pitcher has generated as much fWAR as Lyle Overbay - and as much as Justin Upton, up until yesterday's performance.

Is his success sustainable? Well, obviously not at a 2.30 ERA level. His BABIP thus far has been .267, which is lower than the MLB average of .295, though not abysmally so. A bigger problem could be his home-run rate. He has only allowed three home-runs this year, which is an extremely-low number, especially for a pitcher who has skewed only marginally towards ground-balls. Only 2.7% of fly-balls to the outfield have left the park, which is a lot lower than the expected rate of 7.5%. Some of that may be explained by weak contact, but Miley's line-drive and infield pop-up rates are pretty close to what you'd expect. Sooner or later, those fly balls will leave the park, and his ERA will suffer.

However, that's all relative. His FIP [Fielding Independent ERA] is 2.83, and even his xFIP [FIP adjusted for "normal" home-run rate] is 3.72, perfectly fine for any fifth starter. On the other hand, getting there from his current numbers would involve a rocky period: say, a dozen or so starts with an era around five. We've already been through some harsh regression this year, in Joe Saunders' May outings, and you probably recall, those weren't exactly much fun. That said, if Miley can pitch as he has of late, cutting back on the walks and with more strikeouts, that would soften the landing: fewer balls in play = fewer home-runs, and fewer walks = fewer runs which result.

The Diamondbacks' pitching staff has had its share of issues this year: some starters have struggled, others have been inconsistent, and the bullpen has not been as good as it was in 2011. But, whether starting or relieving, Miley has been perhaps the most pleasant surprise of the season to date. He may or may not be recognized for this in the upcoming All-Star Game, but there's no doubt that, without him, Arizona would be in a significantly worse situation than the .500 record they currently possess.