SURPRISE, Ariz. -- As Kris Bubic wrapped up his final interview of the 2021 season with reporters, the Royals lefty threw a teaser about what a big focus of his offseason would be.

“I’ve been, to be honest, messing around with a second breaking pitch,” Bubic said on Oct. 2, 2021. “Didn’t have enough confidence to throw it in the game. But that’s something I’ll incorporate going forward.”

Five months later, Bubic’s new slider has debuted in his side and live sessions, and he threw two in a perfect 24-pitch, two-inning outing in the Royals’ 10-5 loss to the Dodgers on Saturday night at Surprise Stadium. One jammed Hanser Alberto, who softly lined out to second baseman Nicky Lopez. The other came in a 1-2 count to Max Muncy, who later struck out swinging on a nasty left-on-left changeup.

Bubic threw one more inning on a backfield after the efficient outing; the lefty made his spring debut in relief of starter Brady Singer, who allowed three runs in 2 1/3 innings and struggled early with command before quickening his tempo and finding the strike zone.

“That second inning I had a much better rhythm, it was much cleaner with more efficient outs,” Bubic said. “I’ll take that. Early contact, not too many deep counts, and I was able to mix in all four pitches, as well, which is something I want to emphasize this spring.”

Bubic has wanted to incorporate a new pitch into his arsenal for a few years, going back to the 2020 COVID-19 shutdown. He began tinkering with a fourth pitch last season in his bullpen sessions but never threw it in a game. This past offseason was the first time he committed to getting a feel for the pitch.

Along with trying to gain more velocity and vertical break on his fastball, Bubic focused on finding the right grip on his slider while throwing at his alma mater, Stanford, with his former pitching coach Thomas Eager. Bubic started with a two-seam grip and was trying to create a lot of movement as he released it. But with the way Bubic releases the ball with his over-the-top delivery, it was difficult to get a feel for that grip.

“[Eager] recommended sliding my fingers up toward the top of the horseshoe, and then I told myself to preset it a little bit because if I stay behind it too much, it’s going to look exactly like a fastball,” Bubic said. “I want to have some break. … When I went to that grip, where I was just holding the side of the ball and just trying to throw a fastball with my wrist a little preset, it came out a lot cleaner and had the shape I was looking for.”

Last spring, Bubic didn’t break camp with the Royals, and when he did join them, it was in the bullpen as a long-inning reliever. He moved in between the rotation and bullpen throughout the season, but he established himself as a starter for most of the second half. In the final month of the season, Bubic made six appearances (five starts) and posted a 2.20 ERA in 32 2/3 innings.

“I think I finally realized my strengths, and I’m going to pitch to my strengths,” Bubic said. “I started to understand, ‘OK, I’m having success doing this, I’m going to keep doing this until I see an adjustment from the hitters' standpoint.’ Then you adjust back, and maybe that’s when the slider comes in handy.”

As Bubic assessed the way hitters game-planned against him last year, he realized there was a big part of the plate missing with his current arsenal. His fastball is at its best at the top of the zone and his changeup arm side. His curveball covers the bottom part of the zone.

And glove side? Bubic has been working on establishing his fastball inside against righties, but he still wanted to have a pitch that attacks that part of the plate. Enter the slider, which has a bit of a gyro look to it -- meaning little spin -- and can cut at times.

“I’m not really concerned about the spin itself,” Bubic said. “I’m concerned about the axis it’s taking. As long as there’s a little bit of glove-side action to it, then I’m good with it.

“To have something that can cover all four quadrants -- the hitter has to think about one more thing.”

As Bubic enters his third season in the Majors, any doubt he can place on hitters, any wrinkle they might not be looking for when facing him is an advantage. And Bubic is one pitcher who could appear in any role, especially early in the season. He’s building up as a starter, but he could appear in long relief or in shorter stints depending on what the Royals need.

“If he can have a little bit of movement that gets them cheating, that’s just going to make anything sinking or changing away that much more effective,” manager Mike Matheny said. “It just gives him more weapons.”