Article: One Bill James Study to Give You a Little More Confidence in Cody Bellinger

[Matthew Trueblood]

The key to Cody Bellinger's 2023 resurgence was a profound change in approach, which yielded a huge decrease in his strikeout rate. One essential question around his free agency has been: Is that sustainable?

Image courtesy of © Charles LeClaire-USA TODAY Sports

When he first came up, Cody Bellinger could both hit for power and make contact at a fairly high rate. From 2017 through 2020, he posted a 21.5% strikeout rate (lower than the league average for that span) and a .274 isolated power number, well above the league average. That's a rare and special combination, and it made Bellinger a rare and special hitter. During this period, he won the 2017 NL Rookie of the Year Award; MVPs of both the 2018 NLCS and the 2019 National League; and a World Series ring, which he helped make possible by hitting .243/.378/.595 combined in the NLDS and NLCS in 2020.

We all know what happened next. Bellinger had such an atrocious 2021 and 2022 that the Dodgers cut him loose after the latter campaign. During that span, his ISO crashed down to .162, and his strikeout rate spiked to 27.1 percent. These numbers obviously don't tell the whole story, even if they gesture toward the series of injuries that hampered Bellinger over those years, but they give us the spine of something.

In 2023, with the Cubs, Bellinger batted .307/.356/.525, and while neither his batted-ball data nor his ISO was quite as impressive as at his early-20s peak. his strikeout rate was better than ever. He fanned only 87 times in 556 plate appearances, which comes out to 15.7 percent. In his career before 2023, he'd had an average strikeout rate of 23.2 percent, so in 556 trips to the plate, you'd expect him to punch out 129 times. Compared to his career norms, he trimmed 42 strikeouts from his expected figure. (If you'd like to factor in the fact that he walked less often, too, and thus actually put 64 more balls in play than expected, you're at your leisure. We're only focused on how many fewer strikeouts he generated than was expected, be it by walking, hitting, or desperately tossing the bat backward to create catcher interference.)

That 42 number matters, because back in early 2022, Bill James did a very quick-and-dirty study for his website, BillJamesOnline. Until late last year, James ran that site for many years (with fluctuating levels of help and collaboration) and churned out a largely unsung second act's worth of good sabermetrica, after getting very famous for his first act's worth of (mostly offline) material. Anyway, at the prompting of a reader, James sat down and studied how hitters (like Matt Olson, who had effected a huge drop in strikeout rate in 2021, relative to his first few seasons in the big leagues) follow up after they drastically reduce strikeouts from an established career level.

James found 126 hitters who had a season in which they struck out at least 35 fewer times than would have been expected, based on their career strikeout rates. That's one of the lovely James hallmarks, using a raw number of expected strikeouts conserved, rather than leaning on rates. It hearkens to his early days of exploring this realm, when rates were essentially unavailable and (given the state of home computer technology at the time) unforgivably laborious to calculate en masse. James worked in very simple mathematical terms, often because he had no choice, and he got so used to it that even in 2022, he was still speaking a simpler and more direct numerical language than the one we've embraced online these days, even though he understood and used those more Excel-friendly tools as needed. It didn't just elucidate his study; it also strengthened it. Hitters with greater volume in a given season had a greater chance to cut away the requisite number of expected strikeouts than those with less playing time.

Of those 126 hitters, James found, 116 had a lower strikeout rate after that season than they had had in their careers prior to the punchout plunge. The study took the actual season of that huge change out of the equation, in other words, and still found a lasting effect on the player's strikeout avoidance skills. James admitted a certain measure of awe in that rate of "success," or staying power, north of 90 percent. I share it. That's a stunning finding. 

So, going forward, we should expect Bellinger to hold onto a substantial portion of his newfound contact skills. He might not--in fact, he probably will not--run a 15.7-percent rate going forward, but he's likely to come in south of his 23.2-percent norm. He's a guy who makes contact at an above-average rate, now. That's real, and it should stick around for him, even over the life of a long-term free-agent deal.

Maybe we can also draw some intrigue from the pattern Olson followed, after James performed that study. Prior to 2021, Olson had fanned in 26.1 percent of his plate appearances in the big leagues, and he was a tremendous slugger, with a .254 ISO. In that 2021 campaign, he brought the strikeout rate down to 16.8 percent, but in the two seasons played since then (and since the study that offseason), he's bounced back toward his previous norm: 23.8 percent. That's still a non-negligible improvement upon his previous rate, though, and here's the thing: Olson's ISO in those two seasons with Atlanta has soared to .279. 

I doubt that Bellinger will get all the power that made him the league's MVP half a decade ago back. I doubt he'll remain one of the dozen best contact hitters in the game. Given James's quick study and its extremely convincing results, though, it's reasonable to believe that Bellinger will still be a good contact hitter for several more years. 

This is far short of being the kind of thing that justifies paying a player $200 million, but it should slightly bolster your belief in Bellinger. It's a good time to share it, too, because James recently shared on Twitter that he had a stroke. He's a complicated figure, as firebrands all eventually become, but after shuttering his site last year and with his 75th birthday happening this year, we're running out of chances to celebrate James's foundational importance to the sport and its close observation.

How much store do you set by Bellinger's improved contact rate last year? Do these data make you any more confident about the staying power of his array of recent adjustments? Check out the study here for more information.

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[Bertz]

ZiPS sees him holding onto most of his contact gains, forecasting a 16.9% strikeout rate this coming year.

I think to me the most compelling pro-Bellinger evidence on the power front is still the Isaac Paredes defense. 

https://blogs.fangraphs.com/an-meandering-examination-of-fly-ball-pull-rate-featuring-stars-of-the-game-and-also-isaac-paredes/

Basically if you pull a disproportionately high number of hard hit fly balls, you don't need as many of them to rack up dongs.  And Statcast backs that up, Bellinger hit 26 last year, and if you look at expected homeruns by park

https://baseballsavant.mlb.com/savant-player/cody-bellinger-641355?stats=statcast-r-hitting-mlb#xhr-park

There were 17 different home parks where he would have hit at least 23. 

I don't feel the most confident in this being a repeatable skill (why i still hope for a short term deal), but it wouldn't be crazy to find out it is.

[I owned a Suzuki]

This reply has nothing to do with Bellinger....just wanted to reminisce that how much of my late teen, early 20s Februarys were spent going to the book store every other day to see if James Baseball Abstract was out yet.  I really hope he is still healthy and contributes to baseball discussion for many more years, even though I know he has cut way back in recent years

[We Got The Whole 9]

This is pretty interesting and that is a much higher number than I would have expected, The thing with Bellinger, is his swing will always produce a lot of lofty fly balls that will clear the fence, even with modest EV. So I think it's a safe bet to pencil him in for 25 dongs each year he is adequately healthy. I don't, however, believe that he will always keep such a high BABIP, overall, and specifically as well, with 2 strikes. I'm fine with the belief he will be a 120 hitter for a few years. Is he good enough to block an 80 grade glove in CF with similar intriguing Launch Angle expectations? Is the gap between what you perceive PCA will be and what Bellinger could provide if he sticks in CF big enough to pay 25M for? That's where I think the answer is a pretty clear no. I fully believe PCA is a 3 war player if he is a 95+ hitter, given 500-600 PA. Now can you sign Bellinger and trade PCA for a clear upgrade at 3B, or another young SP? Sure. If that's the plan, I get it.

[Transmogrified Tiger]

I suspect that this finding is similar to one I shared a while back about players with low K rates and steep launch angles, that it is representative of hitting *talent*.  Or if you want to be more precise, bat control and the ability to adjust your swing successfully.  So even in the case that a subsequent season's batted balls aren't quite the same(in terms of quality or quantity), the ability to do this once portends the ability to make a different adjustment to maintain overall offensive success.  This tracks for me given that Bellinger has been successful at different levels of K rate even before 2023, and he's certainly no stranger to high end offensive pedigree given his draft and prospect status(to say nothing of the ROY and MVP on his mantle).

[Backtobanks]

47 minutes ago, We Got The Whole 9 said:

This is pretty interesting and that is a much higher number than I would have expected, The thing with Bellinger, is his swing will always produce a lot of lofty fly balls that will clear the fence, even with modest EV. So I think it's a safe bet to pencil him in for 25 dongs each year he is adequately healthy. I don't, however, believe that he will always keep such a high BABIP, overall, and specifically as well, with 2 strikes. I'm fine with the belief he will be a 120 hitter for a few years. Is he good enough to block an 80 grade glove in CF with similar intriguing Launch Angle expectations? Is the gap between what you perceive PCA will be and what Bellinger could provide if he sticks in CF big enough to pay 25M for? That's where I think the answer is a pretty clear no. I fully believe PCA is a 3 war player if he is a 95+ hitter, given 500-600 PA. Now can you sign Bellinger and trade PCA for a clear upgrade at 3B, or another young SP? Sure. If that's the plan, I get it.

The Cu in CF.bs need a power/middle of the order bat.  Bellinger is that, but I don't think PCA will ever be.  PCA will have value with his skill set, but not in the power department.  Now if the Cubs had 2-3 real power bats, then PCA makes a lot of sense

[Ding Dong Johnson]

26 minutes ago, Backtobanks said:

The Cu in CF.bs need a

The hell happened here?

[squally1313]

44 minutes ago, Backtobanks said:

The Cu in CF.bs need a power/middle of the order bat.  Bellinger is that, but I don't think PCA will ever be.  PCA will have value with his skill set, but not in the power department.  Now if the Cubs had 2-3 real power bats, then PCA makes a lot of sense

We can't just pick and choose which version of Bellinger we like the best though right? He had 26 home runs last year, good for 41st in baseball. That's 6 more than PCA hit last year in the minors (in 56 more PAs). The 'last year was not a fluke' argument still assumes he traded power for contact right? That's not to say that even 85% of 2023 Bellinger isn't very useful, but even the most pro-Bellinger people here aren't expecting a 15% K rate AND 40+ HRs. 

[We Got The Whole 9]

I'm also not sure how you can feel PCA will not hit for power. His swing is geared for lift. Can he make enough contact, will he walk enough are the questions for me. There's legit potential for 280/330/500 in his prime IMO.

[Rcal10]

4 minutes ago, We Got The Whole 9 said:

I'm also not sure how you can feel PCA will not hit for power. His swing is geared for lift. Can he make enough contact, will he walk enough are the questions for me. There's legit potential for 280/330/500 in his prime IMO.

500 slug? I highly doubt that he ever puts that slug up in an entire season in the majors. Also doubt he ever reached OPS of 830. But, damn, I hope you are right. 

[Jason Ross]

6 minutes ago, Rcal10 said:

500 slug? I highly doubt that he ever puts that slug up in an entire season in the majors. Also doubt he ever reached OPS of 830. But, damn, I hope you are right. 

Yeah, I'd agree that a .500 SLG is probably above and beyond. That said, I think an .800 OPS is well within reach. Mike Cameron feels like realistic goal of a prospect like PCA, and Cameron did so six times, with an seventh at .795 (which is really just splitting hairs). Don't want to make anyone think that's a prediction, just that, I think PCA's a guy who has the hit tool, the swing, the power and the speed (he's going to leg singles and turn them into doubles) to make that happen as a possibility. The question for me will be the approach. 

[We Got The Whole 9]

18 minutes ago, Rcal10 said:

500 slug? I highly doubt that he ever puts that slug up in an entire season in the majors. Also doubt he ever reached OPS of 830. But, damn, I hope you are right. 

Why do you have such doubt? He's .515 over 1000 MiLB PA and that is not by virtue of hitting the ball hard. He just has a swing for loft. Give it a couple years and that skill will translate. 

[Rcal10]

56 minutes ago, 1908_Cubs said:

Yeah, I'd agree that a .500 SLG is probably above and beyond. That said, I think an .800 OPS is well within reach. Mike Cameron feels like realistic goal of a prospect like PCA, and Cameron did so six times, with an seventh at .795 (which is really just splitting hairs). Don't want to make anyone think that's a prediction, just that, I think PCA's a guy who has the hit tool, the swing, the power and the speed (he's going to leg singles and turn them into doubles) to make that happen as a possibility. The question for me will be the approach. 

TBF, I said 830 was a bit much. Guess he could do 800 a few times. 

[Jason Ross]

5 minutes ago, Rcal10 said:

TBF, I said 830 was a bit much. Guess he could do 800 a few times. 

There's a reason I teach history and not language arts. Reading comprehension skills ain't it for me.

[mul21]

2 hours ago, Ding Dong Johnson said:

The hell happened here?

[Rcal10]

15 minutes ago, 1908_Cubs said:

There's a reason I teach history and not language arts. Reading comprehension skills ain't it for me.

LOL. I just looked up Manny Machado. What is being described as PCA’s prime years is basically Machado’s career numbers, with a little more slug. Really hope he is right, but that’s a tall order, even for prime years. 

[Backtobanks]

2 hours ago, Ding Dong Johnson said:

The hell happened here?

Somehow the "bs" after the CF instead of after the "Cu".

[Irrelevant Dude]

On a semi-related note, has anyone read "A Fan's Guide to Baseball Analytics" by Anthony Castrovince?  If so, is there anything worthwhile in there?

[chopsx9]

7 hours ago, squally1313 said:

, but even the most pro-Bellinger people here aren't expecting a 15% K rate AND 40+ HRs. 

Speak for yourself 🤠

 

[CubinNY]

I believe if they can get Bellinger on a 5 year deal they will do it. I still believe it’s not the dollars that are bothering Jed, it’s the years. 

[Stratos]

13 hours ago, Backtobanks said:

The Cu in CF.bs need a power/middle of the order bat.  Bellinger is that, but I don't think PCA will ever be.  PCA will have value with his skill set, but not in the power department.  Now if the Cubs had 2-3 real power bats, then PCA makes a lot of sense

PCA's K% jumped pretty high to almost 30% in AAA and in his very short MLB stint.  AAA was a bit of a small sample so we'll see, hopefully that comes down, He's still quite young for that league.  i'd like to see him spend almost a full season in Iowa this year.

I think he might be MLB average in the AVG and power department, and that's where the tool graders show him.  Hitters in the minors are notorious for having inflated BABIP and looks like PCA is no different.  I'd be satisfied if he can put up a 100 wRC+ annually, and hopefully a bit more, with his speed/SB and glove he can still be a good player, even a 4 WAR player.  I don't think he's a .500 SLG guy unless in an outlier year, more like .430-.450 with .255 AVG and hopefully lots of SB.

Edited February 3, 2024 by Stratos

[Stratos]

12 hours ago, 1908_Cubs said:

Yeah, I'd agree that a .500 SLG is probably above and beyond. That said, I think an .800 OPS is well within reach. Mike Cameron feels like realistic goal of a prospect like PCA, and Cameron did so six times, with an seventh at .795 (which is really just splitting hairs). Don't want to make anyone think that's a prediction, just that, I think PCA's a guy who has the hit tool, the swing, the power and the speed (he's going to leg singles and turn them into doubles) to make that happen as a possibility. The question for me will be the approach. 

I dunno, Cameron seemed to be stronger and bigger physically.  PCA isn't a big dude, but he does have the swing lift.  That comp would definitely be on the high end in upside for PCA for me.  I could see fewer HR but potential for more SB than Cameron.

I'm thinking Jackie Bradley Jr with more SB on the low end and Cameron on the high end with probably not as much SLG or BB%.  So most likely somewhere between those 2 guys.  PCA has a lot of Corey Patterson in him.  A bit raw in terms of baseball skills, but very athletic dudes.  I'm thinking PCA isn't as bad as Patterson with the BB% but he's a very aggressive player.