Starting Pitcher SIERA Overperformers

By simply taking the difference between a starting pitcher’s SIERA and ERA, you could quickly identify which guys are likely to be overvalued and undervalued in next year’s drafts and auctions. We do still have a couple of weeks left this season, so things can and will change. But it’s unlikely to change so dramatically so that the players discussed will finish out the year on the opposite list. So let’s talk about some of the biggest SIERA overperformers as these pitchers may be next year’s busts.

A couple of weeks ago, I warned owners about Danny Duffy’s ominous fastball velocity decline trend. Sure enough, several weeks later he was diagnosed with left rotator cuff inflammation. Given the injury concern, loss in strikeout ability and largest discrepancy between his SIERA and ERA among all starting pitchers who have thrown at least 100 innings, he’s an obvious bust candidate for 2015. I had once been a fan as he just had to sharpen his control to deliver profitable returns, but while he has done that, his ability to make batters swing and miss have disappeared. He needs to do both to enjoy a true skills supported breakout.

Yeah, we know Chris Young. You are a wizard.

Doug Fister is just another example of how much luck is involved in BABIP. Last year, he suffered through an inflated .332 mark, likely resulting from the weak Tigers infield defense. It led to an ERA 0.25 points above his SIERA. This year, his fortunes have turned and his BABIP has plummeted to just .271. But what has helped him even more is a superhero ability to strand runners. His BABIP has dropped from .281 with the bases empty to just .255 with runners on, while his skill metrics are fairly similar. The move to the National League didn’t provide the strikeout rate boost we expected and there’s little chance he will continue stranding such a high percentage of runners. He’s unlikely to be overvalued next year, but his ERA is going to jump a full run.

I was Andrew Cashner’s biggest fan last year, but despite a 3.09 ERA that made me look awesome, he was still somewhat disappointing. His strikeouts disappeared and his success was largely due to a low .269 BABIP. This year has been more of the same, but instead of defenders converting balls in play into outs at a high rate, his fly balls have been staying in the park at an unsustainably good rate. His 4.4% HR/FB rate is fourth lowest in baseball. Without the strikeouts, Cashner’s fantasy appeal is in free fall. Overall, his skill set remains good enough to start in shallow mixed leagues, but he might be closer to replacement level than most will expect.

This is the second year in a row that Miguel Gonzalez has outperformed his SIERA and I’m not sure what he’s doing. It’s true that his fly ball and pop-up inducing ways will yield a suppressed BABIP. A .268 mark doesn’t seem too crazy. But there’s simply no way that he will continue to strand runners at a greater than 80% clip. Oddly, his BABIP has actually skyrocketed from .246 to .302 when men have been on base, versus when bases are empty. So that doesn’t explain the high strand rate, especially since his strikeout and walk rates are also a bit worse with runners on. The difference stems from his HR/FB rate — it stands at an inflated 14.8% with the bases empty, but just 5.9% with runners on. That seems like a complete fluke. If he has some magical power to prevent homers on fly balls with men on, why not pitch that way all the time? He’ll likely get drafted in mixed leagues as a back-end starter or reserve and will probably be added and dropped multiple times throughout the season as usual. I wouldn’t touch him.

Lance Lynn is another member of the lucky HR/FB rate club. He sits third among all pitchers, right ahead of Cashner. His strikeout rate is down driven by a drop in his SwStk%, but because of the fortunate HR/FB rate, his ERA has dropped by more than a full run. This is the same pitcher he has always been, one who has trouble versus lefties (his xFIP versus left-handed batters sits at more than a run higher than against righties). He has thrown his fastball more than ever before, and he ranks third in baseball in fastball frequency. That would usually explain a drop in strikeout rate, but his secondary pitches have been so poor that his four-seamer actually leads all his pitches in SwStk%. Without good complementary pitches, it’s hard to bank on long-term success as he ages and loses fastball velocity.

With a line drive rate that ranks sixth highest in baseball and an IFFB% seventh lowest in baseball, how on Earth has Adam Wainwright maintained a .268 BABIP? Beats me! His ground ball rate is at a career low and his strikeout rate at its lowest since 2008. So naturally his ERA is sitting in the mid-2.00 range. If I had just told you about his batted ball distribution, strikeout and ground ball rates, you would have certainly guesses that he has been a bust this year. Nope. He hasn’t changed his pitch mix and his pitch SwStk% marks are generally in line with his past seasons. So this skills decline could be a one year blip or a 33-year-old beginning to show his age. I would not pay the sticker price for Wainwright next season.

About a month ago, Johnny Cueto made my xK% decliners list. His strikeout rate has dropped since, but barely. Cueto has now significantly outperformed his SIERA marks for five straight years. With a fairly league average batted ball distribution, you wonder what he’s doing to generate such low BABIP marks. The Reds have been excellent defensively this year, ranking fourth in baseball in UZR/150 and eighth last year. His O-Swing% has been well above the league average for the past two seasons, and this year his O-Contact% is as well. That would seem to suggest that batters are putting bad pitches into play, which results in weak contact. But that’s just a theory. Still, is that really enough of an explanation to support a .238 BABIP. Doubtful. There’s surely some really good fortune in there as well. And that upward trending LOB% is going to fall below 80% at some point. Without the promise of a repeat of that high strikeout rate, I’m staying away at his likely going rate.

In what has become a trend here, Chris Tillman is yet another whose strikeout rate has plummeted, while his ERA has dropped along with it. Nothing in his batted ball distribution suggests that a .261 BABIP is anywhere near sustainable, but he could thank his defense for making him look marvelous. The Orioles rank first in baseball in UZR/150. That’s the only thing making Tillman look like a viable mixed league starter. None of his pitches generate swinging strikes at even a league average mark. That’s bad. The Orioles defense can’t be his savior forever, and as soon as they fail to make every play behind him, his bubble will burst.