Making Sense of Wade Miley
Excluding Brandon Beachy, who will be sidelined for the remainder of the season due to Tommy John surgery, left-hander Wade Miley has the second-best ERA in all of baseball.
The same Wade Miley who compiled a forgettable 5.08 FIP in his 40-inning cup of coffee with the big league club last season. The same Wade Miley who failed to make our Top 15 D-Backs prospects prior to the season. The same Wade Miley who began the season in the bullpen and didn’t make his first start until April 23 against Philadelphia.
And yet, the 25-year-old Louisiana native boasts a 2.19 ERA and 2.88 FIP, including eight innings of one-run baseball against the Chicago Cubs on Sunday evening. His +2.5 WAR is higher than pitchers more traditionally thought of as aces, such as Cliff Lee, Cole Hamels, Clayton Kershaw, and Felix Hernandez. In his first full season in the big leagues, he is not only a leading candidate for Rookie of the Year, but he also possesses an extreme outside chance to walk away with the NL Cy Young, if his stellar performance continues.
That’s really the question, though. Can Wade Miley continue his unexpected dominance?
His 3.64 xFIP and 3.54 SIERA suggest that his numbers are a bit misleading and due for regression. It seems unlikely that he will be able to sustain a 0.40 HR/9 home run rate and a 4.8% HR/FB ratio, given the home ballpark. Chase Field has the second-highest home run factor (1.832) in all of Major League Baseball to this point in the season, ranking just behind Miller Park. Without extreme ground ball tendencies in homer-friendly Chase Field, one can reasonably assume that the second half of the season will yield more home runs allowed by the southpaw, and thus, more overall runs.
Miley also generates fewer strikeouts and swinging strikes than the average major league pitcher, which should limit his effectiveness down the road. His low strikeout rate is partially due to his heavy reliance on his fastball. Only Bartolo Colon, Justin Masterson, and Lucas Harrell throw their fastball more often than Miley. Of course, a heavy reliance on a fastball does not necessarily correlate to lower swinging-strike rates, but for Miley, it does. He only generates whiffs on 5.0% of his four-seam fastballs and 6.7% of his two-seam fastballs. Despite the plethora of fastballs featured per game, his best pitch is actually his slider, which he throws much harder than he did last season and generates a swing-and-miss 12.4% of the time. It will be interesting to see if he relies more on that pitch in the second half.
When it comes down to it, the former supplemental first round pick in 2008 has found success through limiting walks, limiting home runs, and a friendly .255 BABIP. The home runs should be expected to increase as the season progresses. The BABIP, however, may not rise as much as one would think. The Diamondbacks have the second-best defense in the National League this year, combining for a +16.2 UZR thus far. Miley features a ground ball rate slightly above average at 49.1%, and a quality defense that features John McDonald and Aaron Hill up the middle should help limit some ground ball base hits, while the stellar outfield defense (even without Gerardo Parra) should rob its fair share of base hits, as well.
This isn’t a case where we simply look at the .255 BABIP and call for regression. The Diamondbacks’ defense and Miley’s above-average command should keep the BABIP better than average. Still, the FIP, xFIP, and SIERA numbers all suggest Miley will not be able to maintain his current performance level of a low-2.00 ERA. They certainly suggest an above-average major league pitcher, just not the second-best active pitcher in the league this season. Given the below-average strikeout rate and unsustainable home run rate — especially in Chase Field — it seems acceptable to expect regression in the second half.
Just how much regression will likely be tied to just how many home runs are given up and how well big league hitters can adjust to Miley, now that the proverbial book has been written on him since the majority of the National League has seen him at least once.
J.P. Breen is a graduate student at the University of Chicago. For analysis on the Brewers and fantasy baseball, you can follow him on Twitter (@JP_Breen).
Wade Miley sucks
this comment seems pretty legit
two questions:
1. If his ROS SIERA matches his ERA, wouldn’t/shouldn’t people sign up for that in droves? Isn’t that the better question here: How sustainable is the worst of his peripherals which is still, oh btw, really good?
2. No mention of his BB rate? This is, at some level, the secret of his success, right? In his last 38 innings, he’s walked 2 hitters. Two. You focused on his swinging strike rates, which is, of course, impt, but how sustainable is the BB rate? What has changed YOY or since the minors that has yielded these kind of results?
Really good article. My only quibble would be that the regression arguments are based largely on YTD stats, but his last three starts he has had roughly a 9.00 K/9. If that improvement is for real, then that adds a significant wrinkle to any second-half regression argument. Even if we assume like a 7.5 K rate and 1.00 walk rate going forward, that would put him in pretty elite company.
BABIP of other starters on the staff:
Trevor Cahill: .291
Ian Kennedy: .325
Joe Saunders: .312
Daniel Hudson .346 (limited innings)
Are these guys pitching in front of a different defense than Miley? As a team the starters (with Miley) have a .306 BABIP.
Why again should we not expect SIGNIFICANT regression in his BABIP?
because here at fangraphs, we couldn’t make a statement like that if we actually compared the starters’ BABIPs. its easier to pretend they’re all just machines!
duh
When a player comes out of nowhere, why do stat nerds have to go try to find statistics trying to prove they will regress or eventually fail, etc? I don’t think teams care what all the other statistics are, if you are winning ball games with an ERA in the low-2’s. Sure Miley might have a bad start sometime, but I doubt he is going to regress very much this season. He has been completely dominant all season. I think if he was going to regress or come back down to earth to what some lame statistic says he should be at, he would have done that by now.
This has to be trolling.
I’ll give you a simple answer Travis.
When a player comes out of nowhere and has crazy success, we expect them to regress because that’s all their professional baseball careers have ever told us they were going to do.