Pitcher Advanced Metrics Studs and Duds - SIERA For Week 7

Welcome back to RotoBaller’s Statcast pitcher Studs and Duds article series! Each week, I will select one advanced metric, choose two pitchers with strong values and two with poor values, and analyze what those values may mean for future performance. With about a month and a half of data, I think it's time to take a first look at one of my favorite advanced metrics; skill-interactive earned run average (SIERA).

SIERA is a great metric for capturing a pitcher's independent performance. It quantifies a pitcher's performance by trying to eliminate factors the pitcher can't control on their own. Fielding-independent pitching (FIP) is a stat that also attempts to do this, but unlike FIP, SIERA considers balls in play and adjusts for the type of ball in play. The formula can be found here for those who want to get into the nitty-gritty.

SIERA is a truer indicator of a pitcher's performance than ERA or FIP and can help predict future success or failure compared to a pitcher’s current ERA (which I will do an article on a bit later in the season). It is a great metric for identifying potential buy-low and sell-high candidates, so this will hopefully be a helpful article for those of you taking a look!

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SIERA Studs for Fantasy Baseball

All stats are current as of Sunday morning, May 22, 2022.

Eric Lauer, Milwaukee Brewers
4-1, 2.16 ERA, 2.47 SIERA

Eric Lauer had been a useful fantasy streamer through the first seasons of his career, and he took a step forward in 2021, posting a 3.19 ERA over 118 2/3 innings pitched. He's taken an even bigger step forward so far this season, compiling a career-best 2.16 ERA, 0.94 WHIP, and 32.9% strikeout rate. His 2.47 SIERA supports his peripheral numbers and is fourth-best among qualified starters. What has Lauer done differently, and should fantasy managers buy it?

There are several things under the hood that point to good news for Lauer. The first is his improved control. Lauer's career walk rate sits at 8.3% and his 2021 mark was 8.4%, but he has knocked that down to a strong 4.9% in 2022. The second is his big jump in strikeout rate. This can be attributed to his increased use of his slider from 12.1% in 2021 to 21.3% in 2022. This has been his best swing-and-miss pitch with a 17.2% swinging-strike rate. He has also seen an increase in velocity and spin rate on his fastball, leading to an impressive 15.2% swinging-strike rate. The fact that there are explanations behind his jump in strikeout rate helps me buy it and treat it as legitimate.

Lauer has typically been an under-the-radar fantasy pitcher and has never been a flashy option. He has made considerable jumps in walk rate, WHIP, and strikeout rate so far this season, and his SIERA reflects that. His batted-ball profile itself is actually slightly below average, but his low contact rate and improved other metrics more than makeup for this. He has been a true fantasy All-Star to this point, given his 326 average draft position.

Aaron Nola, Philadelphia Phillies
1-4, 3.96 ERA, 2.52 SIERA

Aaron Nola is a prime example of a pitcher who has pitched well overall throughout his career, but whose underlying metrics have always suggested he could/should be even better. This has been no different in 2022. Nola has a 3.96 ERA, 0.99 WHIP, and 30.9% strikeout rate through his first nine starts and 52 1/3 IP, but his 2.52 SIERA points to an elite pitcher. Should fantasy managers expect Nola's numbers to trend in the direction of what his SIERA suggests?

The answer to this seems pretty straightforward to me, at least in theory. Nothing under the hood seems to contradict Nola's SIERA. His batted-ball profile is fine; his exit velocity and hard-hit rate are in the 42nd and 60th percentiles in baseball, respectively, and his 9.9-degree launch angle is respectable. He has continued to get good results with his main pitch mix of four-seam fastball, curveball, sinker, and changeup and all of his expected Statcast metrics are above-average. The one thing that does stand out is his home runs. Despite his batted-ball profile, Nola currently has a career-high 20.5% HR/FB rate compared to a 14.3% career mark. His SIERA suggests that this has to do with bad luck, and I would agree after looking under the hood.

Nola has seen these discrepancies to some degree throughout his career and has typically hovered just below a true high-end tier of fantasy pitchers. His ERA will always suffer a bit compared to his independent pitching metrics due to the poor defense behind him, but Nola does have all the underpinnings of a next-level fantasy starter. Nola has pitched too well to be considered a true buy-low candidate, but I would consider attempting to trade for him in the event that fantasy managers are disappointed with his mediocre peripherals.

SIERA Duds for Fantasy Baseball

All stats are current as of Sunday morning, May 22, 2022.

Cal Quantrill, Cleveland Guardians
1-2, 3.48 ERA, 4.94 SIERA

Cal Quantrill has had a surprisingly successful career to this point and has compiled decent numbers once again in 2022 with a 3.48 ERA and 1.19 WHIP. He has never been much of a strikeout pitcher, and that has especially been the case this season as he has a career-low 15.1% strikeout rate. Strikeouts do play a part in SIERA, but his 4.94 SIERA is the second-highest among qualified starters at this point. Should fantasy managers worry about Quantrill's drop in strikeout rate and his high SIERA?

Let's first look at the strikeout rate. As I said, Quantrill has always pitched to contact; his career strikeout rate sits at 19.6% and his current contact rate of 84.8% is tied for fourth-highest. However, a drop to 15.1% is a good deal lower than that. The culprit appears to be Quantrill's velocity. He relies heavily on a sinker, cutter, and four-seam fastball and has seen a drop between one and two MPH on each of those pitches. Consequently, he has seen a drop in swinging-strike rate for all of those pitches. He has obviously pitched well despite this, so I don't think there are any injury concerns to be had here, but the drop in strikeout rate obviously limits his fantasy value to a degree.

Certain pitchers historically outperform their underlying numbers, and that can especially be the case with contact pitchers and their SIERA. Quantrill has a middling batted-ball profile but does not strike many hitters out, so his SIERA takes a hit. His strikeout rate is low, even by his standards, but he has pitched well regardless. A lack of strikeouts typically makes a pitcher unappealing for fantasy, but Quantrill has averaged almost 6 IPs per start and has good numbers otherwise. As such, I think he will continue to be a useful back-of-the-rotation fantasy option in both roto and points leagues.

Charlie Morton, Atlanta Braves
3-3, 4.95 ERA, 4.46 SIERA

Charlie Morton came into the season as one of fantasy baseball's more divisive players, with some thinking age and injuries would catch up to him and others considering him to be a great value. I was in the latter camp, but Morton has proved me wrong to this point, compiling a poor 4.95 ERA, 1.45 WHIP, and 20.7% strikeout rate. To make matters worse, his 4.46 SIERA tells a similar story to his peripherals. Is it time to accept defeat, or is there hope for me and fantasy hopefuls?

There are mixed signs, but there do seem to be a good amount of positive underlying signs for Morton. Starting with the not-so-good, he has done a decent job limiting hard contact, but he has allowed a career-high 14.8-degree launch angle (almost twice his career mark) and 41% FB rate. His HR/FB rate is actually strong at 8.3%, but Morton has not been a fly-ball pitcher throughout his career, which could come back to hurt him.

On the positive side of things, Morton has pitched much better in May compared to April. He posted a horrendous 7.00 ERA and 5.18 SIERA in his four April starts but cut that down to a strong 3.27 ERA and 3.83 SIERA in his four May starts. Morton has typically been a slow starter, so this may be all the explanation needed here. Of course, these kinds of splits can be argued as both a positive sign of improvement and also a negative sign of inconsistency, but I am willing to go with the track record and give Morton the benefit of the doubt.

Morton's overall peripherals are still showing a poor for the season, but he has picked things up in May. No one would be worried about him if he had started the season with his May numbers, and it seems like he is more or less back to his old self. I consider Morton to be a strong buy-low candidate, although the window to do so is running out as he continues to turn in better starts.

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