SCOTTSDALE, Ariz. -- Earlier this spring, Joey Cantillo offered a vivid self-assessment of his slider.
“My slider has been pretty dog-water the last couple of years,” Cantillo said. “Honestly, it’s been bad. It’s been something we’ve just kind of hoped to throw in the zone, and it’s been a pitch where you really have to throw it to a great location for me to have the results that I want with it.”
Cantillo is coming off a 2025 season in which he logged a 3.21 ERA over 34 appearances (including 13 starts). Heading into a key spring in which he is competing for a spot in the Guardians’ rotation, he honed in on upgrading his slider to not only make it a more viable option for him in ‘26, but to hopefully make his other, stronger offerings even more effective.
The result? Cantillo made a slight grip adjustment that he and the Guardians hope will pay dividends this season, as the 26-year-old looks to make the next step in his evolution as a big league starting pitcher.
“I’m really optimistic about it from what I’ve seen so far and the profile and what we’ve seen with it,” said Cantillo, who allowed two runs over 4 2/3 innings while whiffing four in Sunday’s 4-4 tie against the Rockies at Salt River Fields at Talking Stick.
Cantillo’s arsenal includes a four-seam fastball (which he used 42 percent of the time in 2025), a changeup (30.5 percent), a curveball (18.8 percent) and a slider (8.7 percent). The first three offerings are his bread and butter, and will continue to be so. But the slider (against which opponents hit .290 last season) nonetheless is a key offering given how it allows him to attack the strike zone in four directions.
Cantillo can run his fastball at the top of the zone and his curveball at the bottom of it. He can run his changeup inside against lefties and away from righties. With the new slider grip (which is closer to his curveball and has downward action), Cantillo has an offering to throw inside on right-handed hitters and hard, down and away from lefties.
In other words: Opponents will have four directions to keep in mind as they make a decision to swing at a pitch or not, via four pitches with unique shapes and speeds.
“[The slider has] always been a strike-generator for him,” Guardians pitching coach Carl Willis said. “But it’s been a little more difficult for him to get it to turn right. We’ve seen a little more of that angle, that horizontal movement with the pitch this spring.
“... It's been good. I think still searching for more consistency, more so with the profile, as opposed to maybe the strike-throwing aspect of it. But I think it’s a pitch that, when he gets it on the plate and to the spots of the strike zone or off that we’re looking for, it's going to be an effective pitch with a little more movement.”
Cantillo’s start against the Dodgers on Tuesday provided a few good examples of how the slider could play off his arsenal. In the third inning against Teoscar Hernández, he threw a first-pitch slider down and inside that Hernández harmlessly fouled into the dirt.
Cantillo came back with a second-pitch changeup that faded off the outer half of the plate for a ball. His next pitch was a curveball down under the zone. Hernández grounded out to third baseman José Ramírez.
Cantillo’s changeup has been a devastating offering for him. Opponents hit just .165 against it with a .270 slugging percentage in 2025, along with a 49.4 percent whiff rate. In a key spot, that’s the pitch he leans on. But he needs other pitches to set it up.
Cantillo isn’t going to suddenly throw 25 sliders each game, but having a refined version of that pitch could pay dividends for him as he looks to break out in the Guardians’ rotation this season.
“I worked with a pitching coach that said, ‘Santa always brings new toys to pitchers at Christmas,’” manager Stephen Vogt said this spring. “Any time you're working on adding a new pitch or a new shape to your arsenal, the tendency can be to throw it too much. I think for our guys, what I've heard Carl say is, ‘We want you to see how it fits into your arsenal.’
“Not necessarily overusing it. Don't put all your focus on it, but see how you're going to use it with your arsenal. So I think, particularly with Joey, we got to keep the main thing the main thing. And that's, ‘Your first three pitches are your best three, and let's see where the slider complements your stuff.’”