2020 Review: Starting Pitcher SIERA Overperformers

Yesterday, I listed and discussed the starting pitchers whose ERAs underperformed their SIERA marks by the most significant margins. I then reviewed the pitchers’ BABIP, LOB%, and HR/FB marks and identified which of the three metrics were driving the SIERA underperformance and what the chances for improvement in 2021 are. Let’s now shift over to the SIERA overperformers. Which of the three “luck” metrics drove such overperformance this season and can that last through next year? Let’s discuss the fantasy relevant names.

Woah, every single one of the 12 pitchers on this list handily outperformed the league average BABIP. That’s one way to overperform SIERA! What’s pretty amazing here is that yesterday, I remarked that the underperformer list wasn’t comprised of many good pitchers, as only three of 17 posted a sub-4.00. Surprisingly, this list is even worse! ZERO pitchers posted a sub-4.00 SIERA, while four were above 5.00, including one above 6.00. That means there is major risk investing in these names in 2021, because if they are unable to maintain luck metric marks vastly superior to the league average, you’re not only left with a worthless pitcher, but one that could potentially do serious damage to your ratios.

Dallas Keuchel
Metric(s) Overperformed: BABIP + LOB% + HR/FB
2021 Regression?You betcha. As an extreme ground ball pitcher, Keuchel relies heavily on his infield defense. He’s had a couple of seasons with a low BABIP, but his career .292 mark is league averageish, which is a feat in itself given that ground balls go for hits far more frequently than fly balls, and he doesn’t induce many pop-ups. The HR/FB rate has no shot of remaining anywhere this low. He’s posted a single digit rate just one in his career, and that was still about double this year’s mark. A rising BABIP and HR/FB rate will bring down his LOB%, which sits about where you’d expect over his entire career given all the grounders erasing baserunners through double plays.

He has now meaningfully overperformed his SIERA each season since 2017, so it’s tempting to believe this is a real skill. Perhaps he learned something late in his career since his ERA isn’t too far below his SIERA for his whole career. That said, given the paltry strikeout rate and the risk his luck metrics move dramatically toward league average, there’s too much risk here to invest, especially if his sparkling 1.99 ERA raises his 2021 cost.

Brad Keller
Metric(s) Overperformed: BABIP + HR/FB
2021 Regression?Yup. Keller is looking like a Keuchel clone where he might have some random years where his infield defense gobbles up all his grounders, and this one was apparently one of them. His Statcast xBABIP, though, was actually the highest it has been since his debut, so it’s not like you can blindly scream that he allows lots of soft contact. On the HR/FB rate front, no one is good enough to consistently allow a mark this low. However, he pitches in one of the most home run suppressing home park, so he should continue to outperform the league average. That said, that outperformance should still result in a double digit HR/FB rate. Interestingly, Keller hasn’t only been a product of his park, as his home HR/FB rate of 7.7% is only barely better than his 8.2% mark in away parks. Like Keuchel, I see no reason to get behind a guy with a weak strikeout rate whose success relies mainly on suppressing hits on balls in play and homers on fly balls. Too much risk and not enough reward.

Chris Bassitt
Metric(s) Overperformed: BABIP + LOB% + HR/FB
2021 Regression? Yes, but not fully. According to Statcast, Bassitt actually mostly earned his low BABIPs since 2018. That doesn’t mean the skills driving the low BABIPs will continue, just that he didn’t have to rely on spectacular defense in the past. It’s anyone’s guess as to whether he could continue doing what he has been to suppress those hits on balls in play. The HR/FB rate, on the other hand, is going to be much more difficult to keep below 10%. However, like Keller, he does pitch in a good park to hold in his fly balls, but not exactly to this degree. Lastly, there’s no way he could sustain that LOB%. Amazingly, Bassitt’s SIERA since 2018 has finished at 4.45, 4.47, and 4.46, respectively, but his ERAs have really bounced around. He’s likely to once again beat his SIERA, but without a strong strikeout rate, there’s not a whole lot of cushion protecting the downside. I would pay for a high 3.00 to 4.00 ERA and if he’s more expensive, pass.

Max Fried
Metric(s) Overperformed: BABIP + LOB% + HR/FB
2021 Regression? Absolutely. Fried’s impressive 11 starts was driven by a trifecta of overperformance in the luck metrics. Like Keuchel and Keller, Fried is an extreme ground baller whose batted balls found gloves at a much higher frequency than in the past. However, Statcast’s xBABIP actually validates that it wasn’t the defense, but Fried’s contact allowed that earned him the low BABIP. That’s a good sign, but those skills were completely missing in 2019. Did Fried suddenly learn how to suppress hits on balls in play or was this just a good 56 inning run? Like some of the previous names, Fried’s HR/FB rate was ridiculously low, which is what could happen when the denominator (fly balls) is low over a small sample of games. Incredibly, his HR/FB rate was cut by 75% from his previous seasons. Despite the expectation for luck metric regression in 2021, he still owns the best skills of the names so far and has the most strikeout rate upside. He’s likely going to be overvalued in 2021 drafts, but he doesn’t have the serious bust potential the previous names have.

Taijuan Walker
Metric(s) Overperformed: BABIP + LOB%
2021 Regression? Yes siree. Having pitched just 14 innings between 2018 and 2019 after recovering from TJ surgery, Walker posted surprisingly strong surface results this season. While the LOB% was a bit high and HR/FB rate a bit low, the majority of his SIERA outperformance was a result of his .243 BABIP. Statcast suggests this was completely undeserved. Walker never posted the strikeout rates his stuff seemingly suggested he was capable of and you have to wonder if he’ll suddenly start to now. He’s still just 28 tough, so he has time to optimize his pitch mix. Unfortunately, none of his pitches have generated a SwStk% higher than 11.9% over his career, so he’s got no strikeout pitch to rely on and would seem to have a lot of work to do to boost his strikeout rate, since the rest of his skills are mediocre.

Dylan Cease
Metric(s) Overperformed: BABIP + LOB%
2021 Regression? Heck yes! Statcast suggests Cease deserved a near identical BABIP as in 2019, yet his BABIP actually fell by a whopping 0.88. How he accomplished that is anyone’s guess, and when combined with the massive decline in strikeout rate, along with the bump in walk rate, you have to wonder what has happened to the former top prospect. While he certainly could surprise us by significantly improving upon his underlying skills and recapturing what it was that made him a top prospect, you can’t pay for that. He’s no more than a dollar days or reserve round option in shallow mixed leagues, with the awareness that he could torpedo your ratios if he fails to improve his skills and his BABIP and LOB% luck dissipate.

David Peterson
Metric(s) Overperformed: BABIP + HR/FB
2021 Regression? Sure. With no MLB history and not even a single inning in Triple-A, we don’t have much historical data to evaluate Peterson’s ability to outperform the league averages. Statcast suggests he did display hit suppressing skills, but it was just 49.2 innings and he posted a .340 BABIP at Double-A and .333 BABIP in High-A. With a low IFFB% and fairly league average batted ball distribution, I’d learn toward him not actually possessing such skills and a BABIP closer to league average in 2021.

Dustin May
Metric(s) Overperformed: BABIP + LOB%
2021 Regression? Absolutely. Like many others, I’m baffled by May’s lack of whiffs and strikeouts given how absolutely superb the quality of his stuff looks. He’s never induced a ton of swings and misses, though, and definitely not the types of strikeout rates you would expect from a top pitching prospect. So this is nothing new. It doesn’t make it any less surprising, however. Anyway, with so many grounders and rarely a pop-up, it’s shocking to see a BABIP so low. This is even more unbelievable given how horrid the Dodgers’ infield defense was, as their UZR/150 marks were far into negative territory at each position. Oh, and that LOB% ranked fifth among pitchers who recorded at least 40 innings. I’m a fan given the grounders and the optimism that his stuff eventually leads to a strikeout rate spike, but there’s clear major regression here.

Julio Urias
Metric(s) Overperformed: BABIP + HR/FB
2021 Regression? Yes, but not fully. Though he owns a normal career .293 BABIP, Urias has posted an almost identical low mark the past two seasons. And, Statcast validates those marks. That likely has a lot to do with his fly ball tendency and high IFFB%. These could be legit skills. That doesn’t explain the super low HR/FB rates though, but perhaps Clayton Kershaw’s HR/FB suppression skills have rubbed off here. For his career, he owns just a 7.5% mark, but we’re still only a little more than halfway to the minimum number of fly balls for HR/FB rate to stabilize. I think the strikeout rate decline is the biggest question now, and of course, wondering how many innings he could realistically go over a 162 game season.

Zach Davies
Metric(s) Overperformed: BABIP + LOB%
2021 Regression? Yyyyyyyyyyes? Davies really kills me as a projectionist as he’s one of the current pitchers who consistently outperforms his SIERA and it’s difficult to determine how. Statcast has not validated his low BABIP marks the last two seasons, suggesting his BABIP skills have remained similiar from 2017-2020, despite it dropping each season. This was his highest LOB% in a season, which makes sense considering this was the lowest BABIP of his career. Since there’s little chance his BABIP remains this low, his LOB% is going to drop closer to his career mark in 2021.

Although he didn’t significantly outperform the league average HR/FB rate, it’s pretty amazing he has kept it in such a narrow range between 11% and 13.1% each season since 2016 considering the home run friendly park he pitches in. How’s he doing that? He’s over the stabilization hump so he’s clearly doing something to suppress homers on flies. The strikeout rate spike was a major positive and driven by a surge in usage of his changeup, his only good pitch. If he throws his changeup this often again in 2021, he should be able to post another 20%+ strikeout rate, but who knows if he’ll maintain the same pitch mix.