Using SIERA To Identify Underachiever Pitchers Who Could Improve for 2023 Fantasy Baseball

March 20, 2023

Dan Palyo's fantasy baseball starting pitcher sleepers for ERA based on last year's SEIRA metrics. These pitchers could bounce back for 2023 fantasy baseball.

As someone who firmly believes that pitching wins championships, I am always on the lookout for pitchers who could outperform their ADP and turn in a big season. I'm a bit obsessed with pitching really, as pitchers are usually the first guys I click into my DFS lineups and strikeout props have been my favorite thing to bet on in baseball for several seasons now.

There are so many statistics in baseball, it's one of the reasons I love the sport so much, to be honest. But not all stats are created equal and some are much more helpful than others when doing our research. Skills-Interactive ERA (or SIERA) has been around now for over 10 years and much like xFIP, SIERA attempts to quantify the skills that underpin a pitcher's ERA.

SIERA attempts to take into account how specific skills (strikeouts, walks, ground balls) interact with each other in order to help pitchers limit runs. SIERA weighs these skills, moving up the skills of pitchers who have high strikeout and/or ground ball rates and low walk rates. What I intend to do is look at some of the biggest disparities between ERA and SIERA from 2022 in an attempt to find some pitchers who should have had lower ERAs based on their skills and who could make nice bounce-back candidates for the 2023 season.

Largest ERA Underachievers in 2022

There were nine pitchers last season who threw 100 innings or more and had a negative differential of one run or more between their SIERA and ERA. Here they are:

It's actually a really interesting list. There are a lot of lefties here (six) and a mixture of some veterans and younger pitchers. There are only a few guys I am going to ignore almost entirely. That would be Patrick Corbin, who has been objectively bad now for several seasons in a row, and Austin Gomber, who pitches his home games in Coors Field and doesn't strike many guys out.

Then, there are three guys with really bad ERAs (5+) and SIERAs in the low fours (Kikuchi, Rogers, Berrios), meaning even if things had broken better for them, they still would have been largely average at best. All three guys have flashed some solid upside so far in their careers and have the kind of stuff that keeps us coming back.

I'll toss Giolito and Greene into the "potential ace" category as both are guys with dynamic swing-and-miss stuff who got hit too hard too often. Manaea probably belongs to that first group based on his profile, though early returns this Spring are good with some reports of increased velocity.

Let's skip an in-depth analysis of Alex Wood for now. We know what he is at this point in his career - an average strikeout pitcher who can give us above-average results when he's getting ground balls, and last year, he got BABIP'ed to death with a .315 mark. He should be fine as an innings eater, but I have no expectations for him to be anything more than serviceable.

Let's look at the other six pitchers and go right down the list (in no particular order other than the one they appear in on my chart).

Trevor Rogers, Miami Marlins

ADP: 337

Baller Move: 262

Rogers is definitely a guy who I think qualifies as a bounce-back candidate. He's just a year removed from a 2021 campaign where he finished with a 2.64 ERA across 25 starts for Miami. Was that season just a complete mirage? I don't think so, though his ERA was probably close to a run too low for his underlying numbers.

And last year pretty much nothing went right for him, especially in the first half of the season when he had only a 20% K rate, but a 10% walk rate. His WHIP was massive in the first half at 1.55, too, and with all those baserunners and only a 66% strand rate, his ERA had nowhere to go but up.

The thing is Rogers seemed to show some signs of reverting to his 2021 form late in the year. His ERA didn't reflect that, but in his final 23 innings pitched in 2022, he raised the K% to 28% while cutting the walk rate down to 6%. He still got BABIP'ed pretty badly at a .356 clip but his xFIP for those last several starts was just 2.75.

On Saturday, Trevor Rogers had 5 whiffs on 9 changeups (56% Whiff%), with an overall 33% Whiff% & 37% CSW%.

✅4-Seamers mostly up
✅Changeups down or out of the zone
✍️Vertical release point was an issue last season pic.twitter.com/bSoqegV9iD

— Corbin (@corbin_young21) March 12, 2023

For Rogers, it really comes down to control and being able to locate his pitches. His fastball is his worst pitch, but it was much worse last year than before because he got behind in counts and had to throw it in hitters' counts or keep throwing his offspeed stuff and risk giving up more walks.

Both his changeup (13%) and slider (16%) had good swinging strike rates. If he did, in fact, fix his release point as is being suggested in the tweet, it could go a long way towards helping him trend back towards a 50% GB rate. He induced only 42% of ground balls last season.

The early returns this Spring have been good, and last year may prove to be more of a fluke (in a bad way) than 2021 was (in a good way). Rogers is likely going to be better than he was last season, even if he isn't able to replicate the numbers from his breakout year in 2021.

He has the stuff to be an effective starter, but he just doesn't have the same margin for error that a hard thrower has in terms of needing to locate his fastball to set up his offspeed stuff. I like his chances of having a solid 2023 campaign with an ERA somewhere in the mid-to-high threes with a strikeout-per-inning upside. I agree with our RotoBaller ranking that his ADP is far too low.

The Verdict: Buy Rogers to bounce back

Yusei Kikuchi, Toronto Blue Jays

ADP: 326

Baller Move: 511

Kikuchi has been a polarizing player in fantasy baseball now for several seasons. We love chasing his strikeout potential, but last year he made managers feel foolish for buying in when he finished with a 5.19 ERA. He's the only pitcher on our list in this article who also finished with a negative WAR (-0.7) and he was a massive disappointment in his first season in Toronto (another one of those guys coming here in a minute when we get to Berrios).

Kikuchi was coming off his best season in Seattle in 2021, but the park downgrade for him in Toronto certainly was not ideal for a pitcher who already had a major home run problem. He saw his ground ball rate dip to a career-low 44% last year and it resulted in a career-worst 23.7% HR/FB ratio.

Now, normally I would be looking at that number and saying that it has nowhere to go but down (the league average is usually around 10%). But Kikuchi's career HR/FB rate now through his first four seasons sits at 19.8%, which is quite troubling and suggests that perhaps there isn't all that much room for improvement unless he changes how he pitches entirely.

The best strikeout numbers of his career came last year, but he also posted his worst walk rates (over five batters per nine innings), too. Perhaps he will be slightly better this year, but I don't see the reward being worth the risk. When you boil it down, he's still a fly ball, HR-prone pitcher who is pitching in an incredibly tough division full of good offenses at a bad ballpark for pitchers. I'm out on Kikuchi, and once again, I'm in agreement with our rankings, which have him well below his ADP.

The Verdict: FADE Kikuchi and expect another inconsistent year

Hunter Greene, Cincinnati Reds

ADP: 125

Baller Move: 104

There is certainly a lot of hype surrounding Greene coming into this season. The Reds just announced he will be their Opening Day starter. Greene, along with lefty Nick Lodolo, is expected to anchor the Cincinnati rotation this season. Both guys had a quick rise to the majors and flashed some major strikeout stuff last season, but Greene had everyone's attention with his ability to hit triple digits with his fastball regularly.

Nearly 2 Minutes of Hunter Greene's Ks at 100 mph or over. 🔥🔥 pic.twitter.com/EFUdb2pVC8

— Rob Friedman (@PitchingNinja) February 23, 2023

Even after gearing down a bit on his fastball after his first month or two in the majors, Greene still averaged 98.9 mph on his four-seamer. The problem with Major League hitters is they are eventually going to time you up, no matter how hard you throw, and his fastball had a 48% hard-hit rate and a .477 xSLG allowed. He was an extreme fly ball pitcher with only a 29% ground ball rate and allowed 24 HR and a 16% HR/FB rate.

The home runs were definitely one of his biggest issues and pitching his home games at Great American Ball Park is going to continue to be a concern going forward if he keeps giving up that many fly balls. His GB% rate in the minors was around 40-42% and he'd be wise to make the adjustments needed to keep the ball on the ground more often (just ask Luis Castillo).

We saw some reasons to think that Greene started to become more of a pitcher and less of a thrower at the end of last season. His second half was simply incredible as he finished his final 35 innings with a 1.02 ERA. Greene saw his K% jump to 36% while dropping his BB% to only 5% and allowing only a .175 AVG to opposing hitters. He started throwing his fastball less often and his slider more, which was a really good thing considering his slider was an elite pitch with an 18% SwStr%.

Can you be an elite pitcher with a high-90s fastball, dominant slider, and lack of a third pitch in this league? I think Spencer Strider proved last season that you can and Greene could be this year's Strider if everything comes together just right.

The Verdict: I am buying Greene to perform up to expectations and he's worthy of taking in the early rounds of your drafts.

Lucas Giolito, Chicago White Sox

ADP: 130

Baller Move: 151

Unlike some of these other guys, there's pretty much one stat that is likely responsible for Giolito's underperforming ERA - a career-high BABIP of .340. His career average BABIP is .279 and the average for all pitchers tends to fall right around .300. Sometimes a high BABIP can be deceiving and bad pitchers who get hit harder than good pitchers SHOULD have a BABIP higher than normal. But it's also a stat we associate a lot with luck as we see balls hit incredibly hard right at fielders end up as outs while dribblers and seeing-eye-singles that are weakly hit end up as hits.

The thing is Giolito's numbers across the board are pretty much the same as they have been for several years in terms of walks, ground balls, and strand rates. His strikeouts dipped and he lost over one full mph on his four-seamer. His slider was less effective, too, and lost one mph in velocity. The 28-year-old's changeup was still his best pitch.

White Sox pitcher Lucas Giolito using a new arm slot.

(🎥: pitchersnation/IG) pic.twitter.com/tB0Wq8IQEX

— Danny Vietti (@DannyVietti) January 20, 2023

His velocity on the fastball this Spring has hovered between 92-94, so it remains to be seen if he can return to his 2020 average of 94 mph. But the new arm slot could go a long way toward getting his slider back on track by helping to tunnel his pitches better and create more deception.

Here's the biggest thing for me. We have seen pitchers bounce back in their late 20s before and become aces again (Kevin Gausman, Robbie Ray) but they are usually the exception and not the norm. The ADP here isn't cheap and likely buoyed by his name and reputation. While he's pitching for a good team in a division where he could pile up wins, I'm a little hesitant to embrace a full buy here.

The Verdict: Giolito is better this year, but don't reach for him at his current ADP.

Jose Berrios, Toronto Blue Jays

ADP: 184

Baller Move: 216

My good friend Eric Samulski stole my thunder here a bit already when he already profiled Berrios here in his "Pitchers with bad fastballs" piece earlier this week. So perhaps I don't need to go into as much detail with Jose as some of these other guys.

We have to ask ourselves, what is buoying his current ADP? He was pretty mediocre in 2020 and the first half of 2021 in Minnesota before coming over to Toronto and fooling a lot of folks into thinking they had fixed him. Sure, his HR/FB rate was the highest it's been in his career. As with Kikuchi, it's not like this guy hasn't had his struggles with the long ball before (though not to the extreme amount as Kikuchi by any means).

His ground ball rate is trending down while his CSW% and SwStr% are both trending down, too. As Eric mentioned in his piece, he once boasted one of the better curveballs in the game. Last year, though, his curveball was the least effective it has been in his career and his changeup was also a pitch with a negative value rating.

I'm just not sure where we expect him to improve, these metrics have all been trending in the wrong direction for a few years and Toronto is a tough place to pitch. Our ranking for Berrios isn't all that much lower than his ADP, but I'm out on Berrios as there are simply too many other pitchers who I think are trending up around that same ADP that are much more worthy of an investment.

The Verdict: FADE Berrios, even with some positive regression, he's a mediocre pitcher at best.

Sean Manaea, San Francisco Giants

ADP: 264

Baller Move: 266

Manaea is perhaps one of the most interesting guys to make our list here. All of his ERA indicators suggest that his 4.96 ERA was not entirely his fault. His xERA of 4.05 and xFIP of 3.96 are both in line with his 3.9 SIERA.

Home runs were a big problem as he allowed 29 long balls last season- 15 of which came in his final 57 innings where his ERA ballooned to 6.44 compared to a 4.11 mark through his first 100 innings. That late-season swoon was largely attributed to a major decrease in velocity as he was topping out around 88-89 mph on his sinker by August.

Sean Manaea's sinker averaged 91.2 MPH last year, which is right around his career norm, so 94-96 MPH is a sizable bump and something to watch this spring. https://t.co/h1NXha7VON

— Jeff Young (@BaseballJeff1) February 26, 2023

His three offspeed pitches (curveball, slider, changeup) all sport solid swinging strike rates. Manaea's overall SwStr% of 13.1% and CSW% of 28.5% are not out of line with where he has been in prior seasons.

If this increase in velocity that is being reported is sustainable, it's going to help him immensely as his sinker is by far his worst pitch in terms of batted ball data. He wasn't throwing it hard and was leaving it up in the zone last year, resulting in a career-low 39% GB rate and a career-high HR/FB of 1.65. We have seen other guys come out of the Driveline program with velocity bumps to mixed results. Manaea will need to sustain that velocity over the course of the whole season, too.

A ballpark upgrade in San Francisco certainly won't hurt either and the Giants have been known to help guys in the middle of their careers rediscover their best stuff (Gausman, Cobb, etc...)

The Verdict: I am buying in on a Manaea resurgence, at this ADP he's worth a gamble.

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