BRADENTON -- So how many pitches does Mitch Keller have in his bag these days?

As of Feb. 25, 2023 at approximately 2:15 p.m. ET, the answer is six: a four-seam fastball, a sinker, a sweeper, a curveball, a changeup and now, a gyro cutter. When it comes to Keller, that number is always subject to change.

“It changes the way they're scouting me and frees up my arsenal,” Keller said, as the Pirates lost to the Blue Jays, 9-7, at LECOM Park. “If one thing's not on that day, I can fall back to another pitch unlike in the past, when I only had three pitches or four pitches, and it limited what I can throw, and I made it easier for their scouting reports.”

For Keller, who threw two scoreless innings with two strikeouts, there are two components of the gyro cutter: a gyro slider and a cutting fastball. Keller uses the same grip for both pitches, but the pitch classification depends on how he throws it. If Keller throws the pitch up in the strike zone and in the 90-mph range, it’s a cutter. If Keller throw the pitch down in the strike zone and in the 85-mph range, it’s a gyro slider.

In his first start of the spring, Keller threw six cutters and one gyro slider. While he throws his cutter and gyro slider with the same grip, there’s an argument to be made that Keller has seven pitches, since they have different movement profiles.

Keller’s throwing of the gyro cutter wasn’t a debut so much as it was a reintroduction. As a rookie, Baseball Savant classified Keller as having thrown a cutter that comprised 20.8% of his pitches, but he said on Saturday that pitch was more of a gyro slider, admitting that he’s never thrown a true cutter. Keller abandoned the pitch following the 2019 season, but he brought it back as a means to attack left-handed hitters, who slashed .276/.359/.390 against him last season.

As he proved last season, Keller can -- and will -- adapt his repertoire.

After re-discovering his velocity, Keller began last season by throwing primarily four-seam fastballs, with sliders, changeups and curveballs mixed into the fold. As the season progressed, he incorporated a sinker and sweeper (a sweeping slider) into the mix. Keller, in a sense, workshopped those pitches on the fly against Major League hitters, and the secondaries became invaluable to his repertoire.

This past week, Baseball Savant added a “sweeper” designation, providing clarity as to how Keller’s slider evolved as the season unfolded.

Keller mixed in a handful of sweepers in his first two starts of the season, then shelved the pitch for a month and a half. On May 25, in one of his two relief appearances, Keller re-incorporated the sweeper, which accounted for about one-fourth of his pitches that afternoon. He sprinkled in the sweeper in his next three starts, but on June 19, Keller began exclusively using the sweeper and abandoned the traditional slider for the rest of the year.

“For him to be able to take a step back and realize what’s going on and actually do something to fix it like last year -- developing the two-seamer and the sweeper in the middle of the season -- then actually implementing those into his game plan and throwing them was incredibly impressive,” said closer David Bednar. “It’s hard enough to try and throw a new pitch, but when you’re doing it in the middle of a season and you’re basically testing it out against big league hitters, and just the confidence he’s had come with it.”

All in all, the sinker and the sweeper, two pitches that weren’t in the mix to begin the season, combined to account for 38.4% of Keller's total pitches. Whereas last season he emphasized velocity and delivery, he dedicated this offseason to refining those pitches, as well as the aforementioned gyro cutter.

With the gyro cutter in the mix, Keller will attempt to stake his claim as the Pirates’ Opening Day starter. Keller didn’t get the nod last year, but following a career year in 2022 with career-bests all across the board, he stands as the favorite to throw the first pitch of regular season for the Pirates.

“It’d be awesome, just to have that recognition,” Keller said. “It's an honor to pitch on that day. To be one of 30 people to do, it would be a huge honor to me."