Starting Pitcher SIERA Overperformers — Aug 23, 2022

Last week, I reviewed the five fantasy relevant starting pitchers most underperforming their SIERA marks. Now let’s flip over to the overperformers.

Vintage Johnny Cueto has returned! Not quite. This is the same pitcher he’s been since 2017, with a mid-4.00 SIERA, and just once has he posted a sub-4.00 ERA during that time. However, this version of Cueto is actually even worse for fantasy owners, as it comes with a career worst 15.3% strikeout rate. That’s significantly below the league average and means that there’s serious downside here if/when his luck metrics regress. Without a strikeout cushion buoying his value, fantasy owners are reliant on Cueto maintaining a positive ERA and WHIP, something I don’t think will continue.

While Cueto’s BABIP is better than average, it’s right around his career mark, so there’s likely no luck involved there. It seems a bit of good fortune comes in the other two metrics, as both his HR/FB rate and LOB% are better than the league average. His HR/FB rate is 13th lowest among 92 pitchers who have recorded at least 100 innings. It’s tied for the second lowest mark of his career, despite pitching half his games in one of the best home run parks in baseball, so the percentage play is that mark goes up.

Moving along to LOB%, his mark is ranked ninth highest among that same population. That’s the third highest mark of his career. Obviously, LOB% is highly influenced by BABIP and HR/FB rate, as lower marks on those metrics is going to result in a higher LOB%. So if/when he starts allowing more homers on his flies, his LOB% is going to drop and ERA going to rise. Given the weak strikeout rate, I probably wouldn’t even want to pick him up in an AL-Only league if I was looking to preserve my ratios.

Has anyone noticed that Tony Gonsolin is leading the NL in ERA and is an absurd 15-1?! It’s bizarre, as his underlying skills are perfectly acceptable, but his strikeout rate and SwStk% has dropped below his career mark, so it’s not like he’s in the midst of a breakout.

Unlike Cueto, who is outperforming on just two of the three “luck” metrics, Gonsolin is doing so in all three. His BABIP is far and away the lowest among all starters with at least 100 innings pitched. The eighth lowest LD% has certainly helped suppress that BABIP, but he has also posted the lowest IFFB% among that population as well. Overall, it doesn’t appear to be a batted ball profile that should result in a significantly below average BABIP. But perhaps he does own some BABIP suppression skills, as he hasn’t posted a mark over .250 over parts of four seasons now. While that may be the case, there’s still no way he’s deserving of a BABIP this low.

Like Cueto, Gonsolin’s HR/FB rate is better than league average, but right in line with his short career. That’s clearly not the primary driver of his SIERA outperformance. Unsurprisingly, the league leading BABIP has boosted his LOB%, which also leads baseball. Gonsolin is doing some crazy things with a skill set that looks thoroughly mediocre on the surface. He likely has some SIERA-beating qualities solely based on how much he has outperformed, but remember, he has still only amassed a bit more than a full season’s worth of innings, so his career sample remains pretty small.

We’re finally getting to see a full season of Michael Kopech in the rotation, and his results haven’t disappointed. But that’s on the surface. Underneath, he has been far less impressive. What happened to his strikeout rate? With a 70 grade fastball that sits in the mid-to-high 90s and 60/70 grade slider, he figured to be a strikeout machine. Instead, both his strikeout rate and SwStk% sit below the league average, which is shocking. In addition to the disappointing strikeout rate, his control has been poor. His double digit walk rate is easily the highest among pitchers with at least 100 innings. When you combine the mediocre strikeout rate and high walk rate with the seventh highest FB% in baseball, you’re left with a scary skill set. That’s potentially a lot of multi-run home runs.

But luckily, Kopech has managed to avoid too many implosions, thanks to a miniscule BABIP. He actually ranks second lowest, well behind Gonsolin, in the metric, which has allowed him to handily outperform his SIERA. Unlike Gonsolin, his batted ball profile does a better job of supporting the low BABIP, though probably not fully. Kopech has posted the second lowest LD% and seventh highest FB% in baseball. That means he has avoided balls in play that go for hits at a high rate and induced more easier outs. Still, it’s hard to believe his true talent level is anywhere near a .226 BABIP, and without even league average strikeout and walk rates, there’s serious risk here of a poor rest of season.

Justin Verlander has made a living outperforming his SIERA, as he has gone 11 of 14 seasons, excluding this one, posting an ERA below his SIERA. This year, his strikeout rate sits at its lowest since 2015 and yet his ERA sits sub-2.00 for the first time in his career. His SIERA is actually at its highest point since 2017, so his underlying skills have regressed, but better fortune has saved him.

Verlander hasn’t posted a BABIP above .272 since 2014, so it’s clear that his batted ball profile suppresses hits on balls in play. He’s been a fly ball pitcher that generates lots of pop-ups, and that’s a recipe for a low BABIP. However, his current .239 mark is the third lowest of his career. While he has also posted the highest IFFB% of his career, he’s likely needed some luck to post such a mark.

Furthermore, after enduring four seasons of a double digit HR/FB rate, his mark has dropped back into single digits, which is where he sat for nine straight seasons from 2007 to 2015, before it jumped into double digits. The low BABIP and HR/FB rate have boosted his LOB% well above his career average.

Verlander has made an incredible comeback from Tommy John surgery, especially at age 39. While his skills have clearly taken a hit, his 3.39 SIERA confirms he remains one of the league’s best. Given his history of outperformance, it probably wouldn’t be very profitable to trade him away and it’ll be difficult to avoid taking a pitching hit given the lack of elite pitchers.

Even after Sunday’s drubbing, Sandy Alcantara is still significantly outperforming his SIERA. Armed with a high-90s fastball, I think everyone continues to wait for the major strikeout rate spike, but it still hasn’t come. You would figure someone with his stuff would be capable of mustering better than just a marginally better than league average strikeout rate.

Though we continue to hope for more strikeouts, the rest of his skill set remains strong. His control improved last year and has continued this year, while his FB% sits above 50% for the second straight season. That’s everything I want from a starting pitcher, though I don’t mind the fly balls as much now in this lower HR/FB rate environment.

Alcantara has benefited from a low BABIP, though not significantly lower than his previous mark. It’s rare to find a ground ball pitcher who has also generated a double digit IFFB%. But since he doesn’t allow that many flies, it hasn’t led to a significant number of pop-ups. Offsetting the high GB% is a low LD%, which has been driven by his changeup. That pitch has allowed just a 10.8% LD%, and leads his pitches with a .221 BABIP. Aside from the low BABIP is a 6.4% HR/FB rate, which is eighth lowest in baseball. High ground ball pitchers usually allow a higher HR/FB rate than high fly ball pitchers, but we aren’t seeing that here.

Overall, I like his skill set and still have hopes of a strikeout rate spike in the future. But he’s clearly benefiting from a low BABIP and HR/FB rate that isn’t all that likely to continue. Yet, even with regression the rest of the way, I expect him to remain one of the better fantasy starters.