Inside the 40: Brad Keller
Brad Keller was the biggest addition to the Phillies bullpen, and maybe the biggest addition to the entire roster this offseason.
Welcome to the first “Inside the 40.” If you couldn’t tell from my introduction article, I’m really, really excited about this new journey on Substack.
I’m going to go in-depth on every player on the 40-man roster for the next 40-50-ish days. This should take us up to Opening Day, which is 51 days away. Some players I’ll write about aren’t on the 40-man yet, like Justin Crawford and Aidan Miller, because how can you not write about them right now?
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Alright, let’s talk Brad Keller.
Inside the 40:
Could you tell me who drafted Brad Keller? If you didn’t know, the answer is the Arizona Diamondbacks in the 8th round of the 2013 MLB Draft. Keller was set to play college baseball at Presbyterian College, but elected to go right to the pros after the draft.
If you go down Keller’s Baseball Reference (which we’ll be doing a lot of over the next two months), it’s not pretty. Lots of early-career ERAs in the 5s. Keller burst onto the scene in 2018 with the Kansas City Royals, tallying a 3.08 ERA with 96 strikeouts in 140.1 innings. It was a promising rookie year in the majors. Then, it sort of all went down hill.
ERA Per Year
2019: 4.19 in 165.1 IP
2020: 2.47 in 54.2 IP
2021: 5.39 in 133.2 IP
2022: 5.09 in 139.2 IP
2023: 4.57 in 45.1 IP (right shoulder impingement syndrom)
2024: 5.44 in 41.1 IP
2025: 2.07 in 69.2 IP
So the biggest question with Keller is…what changed?
A couple of things, but I don’t know if the Cubs, or maybe even Keller himself, thought he’d have as good of a 2025 as he did. His contract was selected by the Cubs to make the Opening Day roster after signing a minor league deal at the beginning of the calendar year.
The sweeper that changed Brad Keller
Brad Keller threw his sweeper just 6.3% of the time in 2024 where he struggled immensely. Hitters only hit .200 against it, but it had just a 27.3 whiff% at an average of 83.8 mph. It was a pitch that hitters could get ahold of. Keller’s opponents were barreling 10.5% of his pitches in 2024. Something needed to change.
Keller’s sweeper had a putaway% 24.5% in 2025. It has a whiff% of a whopping 45.8%. Keller and the Cubs pitching staff cut 7 points of vertical drop off of his sweeper from 2024 to 2025. That’s what seemed to be the difference.
What I always find funny about professional athletes and analyzing their game is that you can watch film, look at in-depth numbers, and still be impressed by some of their answers.
Back when Keller was introduced to the media, he said that his sweeper “rode a bit of a rollercoaster” in 2025, and he wants that to be a focus this current offseason. Keller wants to implement it more to lefties, which would elevate his game even more. He threw it to left-handed hitters just 10 times, while righties 151 times.
Where does Keller slot?
It’s pretty obvious that Keller will be the setup man. If an 8th-inning matchup heavily favors a lefty, then that could change, but the 8th inning seems to be Brad Keller time.
I’ve talked about this all offseason, but I’m loving the Phillies’ approach with the bullpen this offseason. I think it has the chance to be a really good bullpen. They’re not throwing 1-year darts at aging relievers whose stuff is declining. They’re finding younger, controllable guys that they know they can help improve.
What does it say about the Phillies offseason that Brad Keller was their best addition? I don’t know, that’s for you to decide. But his stuff is legit. He’s coming off the best year of his career as a late-inning leverage guy.
Brad Keller and Jhoan Duran back to back is going to be absolutely filthy.