Using SIERA to Identify Overachievers Worth Fading in 2024 Fantasy Baseball

February 11, 2024

Casey Wilson evaluates starting pitchers who could see negative ERA regression in 2024 fantasy baseball. based on last year's SIERA metric. These SP could be overvalued draft targets and sleepers.

With spring training rapidly approaching, it's time for part one of my two-part series on using SIERA to identify pitchers with an ERA that was not truly reflective of their overall effectiveness. SIERA attempts to quantify the skills that underpin a pitcher's ERA. It attempts to consider how specific skills (strikeouts, walks, ground balls) interact with each other to help pitchers limit runs. SIERA weighs these skills, moving up the skills of pitchers with high strikeout and/or ground ball and low walk rates.

Last year, my colleague and good friend Dan Palyo wrote this article. On that list were some notable names. The most notable were Alek Manoah, who had a -1.61 difference; Dylan Cease, who had a -1.28 difference; and Martin Perez, who had a -1.19 difference. This helped our members avoid these names in drafts, which ultimately, as we know now, were significant decisions.

Today, our goal will be to distinguish which players to buy into the numbers. We will focus only on the overachievers, the pitchers whose ERA was the lowest compared to their SIERA. I will warn you that I tend to trust the numbers and will likely avoid some big names on the list below.

Largest ERA Overachievers in 2023

We have an exciting mix of big-time names and easy fades from the list above. We will start our journey by breaking down some names that are being drafted in the top 75 of most drafts and work our way down to some less impactful decisions. Although making this list is a red flag, it does not mean every name listed above is not draftable.

Top of the Board (Top 75 ADP)

Gerrit Cole, New York Yankees

ADP: 11.7

RotoBaller Ranking: 13.0

We will start by bursting out of a cannon as the top two names on our list are the reigning Cy Young Award winners in their prospective leagues. Although Cole is at the bottom of the list, his SIERA was a whole point higher than his 2.63 ERA.

If not for his Cy Young Award last season, Cole would be on the short list of those being talked about regarding decline. His 27.0% K% was his lowest mark since 2018 and was 5.4% points lower than his 32.4% mark in 2022. The same goes for his 11.7% SwStr, 2.6% below his 2022 mark.

The biggest concern is the drop in his stuff. His fastball averaged 96.8 mph last season -- his lowest since 2018. His slider, his main out pitch, went from 44.2% Whiff% in 2022 to 32.9% Whiff% in 2023. His curveball was similar, decreasing from his 36.9% mark in 2022 to his 24.4% mark last season.

Cole's market value, the decrease in his stuff, and glaring differences in his ERA and SIERA make him an easy pass as the second pitcher coming off the board. I would expect to have zero shares of Cole this season.

Blake Snell, Free Agent

ADP: 56.0

RotoBaller Ranking: 52.0

Blake Snell, like Gerrit Cole, is our reigning Cy Young award winner, this time from the National League. Snell has a ton of question marks heading into 2024. The biggest one to note is where he will play. Without knowing a landing spot, we can only evaluate Snell from what he did last season.

When digging deeper into Snell, we note some very interesting things. First off is the walk rate. Snell posted a career-high 13.3% BB%. You rarely see a pitcher post under a 2.25 ERA with a 13.3% BB%. As our own Eric Cross notes, only 10 pitchers have done similar since 1916.

Blake Snell currently has a 2.32 ERA and 13.5% walk rate.

Only 10 pitchers since 1916 (farthest back Fangraphs has BB%) have had an ERA under 2.50 and a walk rate above 13% in a season of more than 100 IP.

The last was Chuck McElroy for the Cubs in 1991.

— Eric Cross (@EricCross04) September 25, 2023

Second off is the innings. Snell has only thrown over 129.1 innings twice in his eight-year big league career. Interestingly enough, he won a Cy Young both times. He reached 180.0 innings last year while only reaching the seven-inning mark in three of his 32 starts.

The third most significant factor was the luck. We already noted the difference in his SIERA and ERA, but Snell also has some drastic numbers in other areas. His .256 BABIP was 0.51 points lower than his 2022 mark. His 86.7% LOB (left on base) mark was the best in baseball. A whole 6.3% point higher than the second best, which so happens to be Gerrit Cole and Kodai Senga.

Snell's strikeout numbers are elite. He finished last season with a 31.5% K% and a 15.3% SwStr%. His curveball, changeup, and slider had a Whiff over 45%, only one of baseball's two starters with three pitches above the 45% plateau.

With the amount of unknowns and market value for Snell at the current moment, I will pass on him and focus on getting my exposure in certain matchups during the season in DFS.

Kodai Senga, New York Mets

ADP: 60.0

RotoBaller Ranking: 66.0

Kodai Senga is in the complete opposite boat of the two arms listed above, and although appearing on this list, he remains one of my favorite arms to target at his current ADP.

Senga finished his rookie campaign with a 2.98 ERA, .206 BAA, 1.22 WHIP, 44.7% GB%, 29.1% K%, 12.5% SwStr%, and 11.1% BB%. He led all rookies in ERA and K% and only improved as the season progressed.

In the second half of the season, Senga posted a 2.58 ERA, .212 BAA, 1.15 WHIP, 42.8% GB%, and 28.6% K%. The most encouraging thing was the 9.6% BB% in the second half, a significant improvement from the 13.0% BB% he posted in the first half of the season.

His ghost fork remains one of the best pitches in baseball with a .110 BAA, .147 SLG, .195 wOBA, and a 59.5% Whiff%. His cutter is also an elite pitch with a 17-run value, and his four-seam fastball is serviceable but can touch triple digits.

Despite the difference in ERA and SIERA, Senga was one of baseball's best second-half pitchers and should be a player we target heavily in drafts.

Middle Rounds (100-200 ADP)

Tanner Bibee, Cleveland Guardians

ADP: 103.7

RotoBaller Ranking: 134.0

Like Kodai Senga, I am not concerned about sophomore pitcher Tanner Bibee, who is coming off an exceptional rookie campaign. Bibee burst onto the scene with an eight strikeout and a 27% Whiff% outing in his big league debut, and he never looked back.

He tied with Senga for the best ERA for rookie pitchers with a 2.98 ERA. Bibee posted a 24.1% K%, 7.7% BB%, .228 BAA, and a 1.18 WHIP.

The only concern for Bibee is the amount of HRs given up last season, especially on his fastball. His 10% HR/FB was third-best in the league among qualified pitchers. His 36.8% GB% also proves he is due for some negative regression with the long ball in 2024.

Bibee should provide solid value next season and is a fine pick at his current ADP. The 103.7 ADP is a little overvalued, but Bibee is a young arm with much room to grow.

Sonny Gray, St. Louis Cardinals

ADP: 114.0

Rotoballer Ranking: 93.0

Interesting story about Sonny Gray. In my first-ever career college baseball game, we played Vanderbilt, and Sonny Gray was on the bump for them. Since then, I’ve rooted for him and have always loved how he competes and conducts himself.

That said, Gray is an easy cross-off this season and an arm I will have zero shares of.

Let’s start with the good. Gray has dominated the past two seasons, posting a 3.08 ERA in 2022 and a 2.79 ERA in 2023. He did this with a 24.3% K%, .225 BAA, and a 1.15 WHIP.

His sweeper is an elite pitch and one of the best in baseball. Gray throws it 20.4% of the time and does it with a ton of success. He didn’t allow an HR on this pitch last season and posted a .097 BAA, .118 SLG, and a 41.3% Whiff%. It’s a weapon that he will deploy often.

Now, let’s get to the bad. Gray was extremely lucky last season. His 0.39 HR/9 was historically low for a starting pitcher. This led the MLB by a wide margin. Next in line was Justin Steele, who posted a 0.73 HR/9. For comparison, in 2021, Gray posted a 1.26 HR/9 (albeit in Great American Ball Park), and in 2022, he posted a 0.83 HR/9.

Gray has been good at limiting the long ball in his career, but the home runs are due for some negative regression, and getting out of Minnesota may not be the best thing for him as his two most dominant seasons in the big leagues came in a Twins jersey.

Justin Verlander, Houston Astros

ADP: 120.3

RotoBaller Ranking: 110.0

Verlander is so incredibly talented that I can’t say anything wrong here. He continues to impress year in and year out and put up monster seasons. He is an absolute workhorse that will eat up innings on your fantasy team and provide a solid floor.

His 21.5% K% was the lowest in his last six seasons in the big leagues, so there is some pause for concern. The thing with Verlander, though, is that he knows how to pitch.

There isn’t a stat for pitch ability and the ability to outsmart opponents with experience, but Verlander knows how to do just that. You can’t value that, and because of it, I will always endorse a pitcher like Verlander. The dude gets people out, and he’s been doing it at the big league level for the past 18 seasons.

Jordan Montgomery, Free Agent

ADP: 135.7

RotoBaller Ranking: 124.0

Montgomery is impossible to evaluate here until he finds a landing spot. He was incredible in the postseason for the Rangers and was a crucial cog in their World Series title. I expect that momentum to roll over into the 2024 season and Montgomery to be a force.

He was much better for the Rangers than the Cardinals. In 21 games with the Cardinals, Montgomery posted a 3.42 ERA, 21.2% K%, .250 BAA, and a 1.25 WHIP. After the trade to the Rangers, Montgomery had a 2.79 ERA, 21.6% K%, .240 BAA, and a 1.09 WHIP.

I'm buying into Montgomery taking a big step forward after bursting onto the big stage in the playoffs. Still, as said earlier, it is impossible to evaluate fully until we know where he will pitch in 2024.

The Rest of the Bunch (200+ ADP)

A few other names on this list are being taken outside the top 200 picks of drafts -- players like Wade Miley, Michael Wacha, Josiah Gray, and Bryce Elder. With players like this late in drafts, I am looking for guys who possess upside and who may have been a bit unlucky last season. It’s the opposite for them, and regression will eventually get to them.

J.P. France and Mike Clevinger are going undrafted, and rightfully so. Clevinger was a popular value DFS player late in the season last year, but that is his value, and he is not someone I want to be tied to in a season-long league.

Last but certainly not least is Hall of Famer Clayton Kershaw. Kershaw recently signed a one-year deal to return to the Dodgers in 2024. He will be placed on the 60-day injured list to start the season and rehab his shoulder, which required surgery in November. We want to avoid Kershaw in redraft leagues, as there is no clear-cut date on exactly when he will return, but I don't mind the idea of taking some late fliers in best ball and hope we catch some 2022 form late in the season.

Download Our Free News & Alerts Mobile App

Like what you see? Download our updated fantasy baseball app for iPhone and Android with 24x7 player news, injury alerts, sleepers, prospects & more. All free!

More Fantasy Baseball Advice