Spencer Strider's New Curveball Could Lead To Frightening Results In 2024

Image credit: Spencer Strider (Photo by Matthew Grimes Jr./Atlanta Braves/Getty Images)

A meteor hit baseball on Opening Day in 2022. That evening, Spencer Strider came out of the bullpen against the Reds to work two perfect innings while striking out five.

The 2020 fourth-round pick out of Clemson had officially debuted the year prior, but many still overlooked the mustachioed fireballer despite his rise from Low-A to the majors that season while pitching across five different levels.

While he began breaking Stuff+ models right away, Strider’s ascension to stardom didn’t happen overnight. He struggled with his control over his next few appearances in 2022, rebounded to rattle off a dominant run, and worked his way into the rotation in late May.

Strider’s rookie year was historically great. Among pitchers with at least 130 innings in a single season, he ranked third all-time in strikeout percentage, 11th in K-BB%, and 19th in swinging strike rate.

The walk percentage, which was the biggest worry early on, improved throughout the year:

Strider did this while throwing just two pitches—his fastball and slider—over 95% of the time. History told us that starting pitchers usually need three reliable offerings to turn a lineup over multiple times. The question became, could Strider replicate his success over a full season of starting?

Historically Great (In Some Ways)

Before Blake Snell pulled away late, the 2023 National League Cy Young race was as much about what voters valued in a pitcher as it was about who was having the best season.

This chart shows the six leading vote-getters who also happened to be the NL fWAR leaders.

More stats could’ve been included to paint a fuller picture of the award race, but keeping things tight also has its benefits.

It’s interesting to see how statistically different each pitcher was from the others. We didn’t necessarily have a situation where one hurler was so clearly above his peers.

Do you value ERA the most? Then Snell was your choice, and bWAR backed you. What about strikeouts and walk avoidance? Strider lapped the field in this category. Wheeler had the edge according to fWAR, which correlates with strikeouts, walks, and homers, while viewing Snell’s case as the weakest of the bunch. Webb is close to Snell in bWAR and walked less batters. His ERA was solid, but not as shiny as Snell’s.

When did the Cy become the ERA award? As Eno Sarris noted in September, ERA isn’t just “the pitcher’s results.” It’s “the results of the pitcher and defense combined.” (and even the ballpark, too!) Of course, the Cy shouldn’t be the “alphabet award” either, as someone called it in my “X” mentions as a rebuttal to my late-season case for Strider to win (before it became clear that it would be Snell).

Admittedly, the alphabet award is a hilarious name for the honor given to a pitcher who dominates in K%, SwStr%, FIP, etc. In his case, Strider wasn’t getting the results, though.

While ERA isn’t as much of a pure results stat as many want to believe, one can’t deny Strider’s 3.86 mark was a bummer.

It was also confusing when looking at his alphabet stats.

Strider didn’t just post good underlying metrics last season. He was historically dominant:

In addition to leading MLB in the above metrics (plus xFIP), his strikeout rate was the fourth-best of all time.

His swinging strike rate, which Fangraphs has data for going back to 2002, was the best ever.

So why wasn’t his ERA better?

Potential reasons

Having already mentioned how defense could contribute to a pitcher’s ERA, it’s worth noting the Braves’ ranks from last season:

DRS: 15th out of 30
UZR: 27th
OAA: 22nd

When using Statcast data to determine the defense’s performance behind a pitcher while he was on the mound, Strider grades out as exactly neutral.

So let’s put that aside. If anything, we can say that Atlanta’s defense probably wasn’t helping last year.

Did Strider possibly get unlucky? His ERA estimators sure seem to think so:

By so many pitching metrics, Strider was either very good or historically elite last season, yet his ERA severely underperformed.

His .316 BABIP was high but not deadly, and his 70.3% left-on-base rate was low but not drastically so.

His HR/9 was abnormal compared to other aces, but there isn’t one stat to point to and say, “This is the reason.”

Digging deeper into the homer numbers, 10 of the 22 he allowed came with men on base. Strider allowed a low batting average the third time through the order, but his slugging increased, and (once again) 10 of the 22 he allowed came in these situations.

It felt like this while watching him in 2023—dominance for most of his start before a late homer was given up with men on base.

So that’s it. If Strider does everything the same as last year, he has a floor of a mid-3s ERA and 260 or more strikeouts. Based on how things went in 2023, there’s some hope that he’ll run hot in any upcoming season. And that’s that.

(Sudden record scratch noise)

A New Hope

Here’s the thing—Strider isn’t just running it back. He’s now throwing a curveball.

As Lance Brozdowski recently noted in his Substack, the sample is frighteningly small, but there is reason to believe his new pitch will grade out favorably.

We asked Brozdowski to elaborate on how Strider’s curve could specifically help against lefties:

“As far as how the curve would help versus lefties, the downward action of curves, especially at reasonable velocities, is hard for lefties to do damage on from righthanded pitchers. This is partially why sweepers perform poorly from righties to lefties—they lack that drop. So the Strider curve, based on the small-sample specs we have, should be at least an average pitch per stuff models.”

He later added:

“The sneaky part of the shape of his curve is that it has a lot of horizontal movement or sweep. So I think there’s a chance he uses this more versus righthanded hitters than we think.”

We still don’t know if Strider can reliably throw his curve at good locations throughout an entire season, but it’s easy to see how much more upside Strider has if he can.

There’s an argument to be made that natural regression could lead to a unanimous Cy Young-type season from Strider in 2024. A new curveball, which would give him more options later in starts when he gave up all those homers last year, raises both his floor and ceiling.

As a reminder, Strider totaled 281 strikeouts and won 20 games while throwing his fastball and slider a combined 92.7% amount of the time.

Now, he might have another above-average weapon.

There’s no ceiling on his ability to lap his peers statistically this season.