Brad Keller found success as a reliever — pitching much like a starter

Brad Keller is two seasons removed from his days as a starter, and his bullpen transformation has come with the upsides that teams usually hope for: a velocity uptick (though his was more dramatic than is normal), higher whiff rate, more strikeouts, better production.

You don’t have to squint, though, to see remnants of who Keller was as a starter. After all, he still pitches a lot like one.

Keller is a rare five-pitch reliever, and none of his offerings are footnotes in his arsenal. He throws his four-seam fastball, which jumped a remarkable 3.4 mph last season alone, over 42% of the time, but the remaining approximately 58% is a fairly even split between his slider, sweeper, sinker and changeup.

In his breakout 2025 season, his first as a back-end reliever, which netted him a two-year, $22 million deal with the Phillies, all of them were effective, too. 

Measured by opponent slugging percentage, Keller’s worst pitch was his slider. Hitters slugged .389 against it. No other pitch yielded an opponent slug above .295. Three — his changeup (.189 AVG, .216 SLG), sinker (.147 AVG, .147 SLG), sweeper (.067 AVG, .133 SLG) — were dominant. 

Speaking to reporters on Monday via Zoom, Keller outlined why he stuck with the full suite he deployed as a starter, and the reasoning goes something like the old saying: If it ain’t broke, don’t fix it. 

“I felt like I had good command of all the pitches, and they were moving pretty well,” Keller said. “So as long as I was able to do that, I feel like we were just gonna continue to roll with all five pitches. I think it helped out a lot.”

Keller also wanted to remain unpredictable to any given hitter. He didn’t want to fall into the trap of relying on just a couple of his pitches — sinker and slider to righties, for example, then four-seamer and changeup to lefties — depending on the handedness of the opposing hitter. Last year, he threw three of his pitches at least 15% of the time to lefties, and four of them at least 18% of the time to righties. 

That formula — particularly the latter, hyper-balanced one to righties — makes plenty of sense for the Phillies to follow in 2026. Righties slashed .148/.243/.222 against Keller last season.

Especially in his first year as a full-time reliever, with new routines, workloads and schedules to adjust to, the distributed spread also gave Keller a fallback. 

“Obviously, you’re not gonna have your best command of every single pitch every time you go out there,” he said. “So, it was nice to have options, where it’s like, ‘OK, four-seam’s not as sharp as I want it to be, I can rely on the sinker here a little bit more. I can rely on the sharper slider if the sweeper’s not moving as well.’ Things like that. I think it just kinda gave me a little bit of a backup plan when things weren’t as sharp day in and day out.”

Now, with that full year as a full-time reliever under his belt, and with the security of a two-year MLB contract as compared to the minor-league deal with which he entered the 2024 season, and with a new pitching staff counting on him as its top right-handed bridge to closer Jhoan Duran, expect Keller to get even more creative. 

Before signing, Keller spoke with pitching coach Caleb Cotham about their pitching philosophies and ideas for how to get the most out of his arsenal. There was alignment, Keller said, in the way they each think about pitching.

“He kinda brought up some ideas of things that we feel like would be fun things to try,” Keller said. “Like, throwing sweepers to lefties, changeups to righties, things like that that’s kind of a little unorthodox.

“I really liked how he thought about pitching. Super cool guy, young guy, really relatable. It was awesome. Our talks were great. Really helped me out and feel like I was comfortable landing here. A pretty smooth transition from what I learned last year, what I even learned the year before with the Red Sox, just kinda rolling right into this year.”