KANSAS CITY -- In big moments Tuesday night, Royals starter Kris Bubic went to his newest pitch. He struck out Toronto outfielder Daulton Varsho with a slider to end the third inning and came back to punch out Santigo Espinal in the fourth inning with his slider in the fourth.

Bubic was dealt the loss in the Royals’ 4-1 defeat to the Blue Jays at Kauffman Stadium, but the new look and addition to the lefty’s arsenal was on full display through five innings of two-run ball.

“I think the confidence is growing with it,” manager Matt Quatraro said of Bubic’s slider. “Doing it against a team like this is only going to help. Using it in big spots, good hitters. I don’t have any question that there’s a commitment to doing it. He’s working on it, he believes in it, he’s seen good results, he knows the data’s right. So I have no doubt he’s going to keep doing it.”

Besides some early standout defense, the Royals didn’t do much to back Bubic up, with the offense mustering just four hits off the Blue Jays’ pitching staff. Franmil Reyes’ 455-foot home run was one of those hits off starter Yusei Kikuchi; third baseman Matt Duffy knocked the other three.

“Other than the two mistakes on me, everything else was absolutely dotted based on what I was seeing,” Duffy said. “He can get erratic at times, and we had talked about that in the report, to try and put the pressure on him, but we really didn’t. We were on our heels from the start. He had really good stuff tonight.”

Bubic did his best to match Kikuchi, but the Blue Jays did put the pressure on the Royals’ starter. Bubic threw 88 pitches in five innings, and the Royals needed all five of those based on how short the bullpen was Tuesday in the midst of a 12-game stretch on the schedule.

“I would have liked to keep the pitch count down a little early,” Bubic said. “Got ahead in counts and then in the middle of at-bats, threw some pitches outside the zone. Had to come back in with two strikes and made some mistakes over the middle of the plate that they hit. But overall, I thought the stuff was good.”

What stood out, and what Bubic can build on, was his pitch usage. Bubic threw his fastball 40 percent of the time, distributing his secondary pitches much more effectively. He dropped in 23 curveballs and 21 changeups, and that new slider that was the talk of Spring Training again this year? Bubic threw nine of them, registering five swings and three whiffs on the pitch.

He’s planning on using it more against lefties, like he did with Varsho -- who homered in the sixth off Carlos Hernández -- on Tuesday.

“I’ll continue to work it in, obviously with the heavy right-handed lineup they have tonight, the changeup was the go-to offspeed, especially to a lot of the righties,” Bubic said. “The slider felt good. Sometimes it gets a little big on me, kind of blends with the curveball, but I’m happy it’s in the arsenal and happy I’m mixing it in.”

This season, Bubic’s fourth in the Majors, is a massive year for the lefty still trying to establish himself in the Royals’ rotation. He’s coming off a 3-13 season last year, when he posted a 5.58 ERA. He entered the spring with something to prove -- to the new coaching staff, but also to himself.

And that centered around bringing his slider back -- not only toying with it in bullpens, but committing to it in games.

“Just having this shape, another speed to cover,” Bubic said. “Usually, on most nights, it’s probably a little easier to command than the curveball. I was a little erratic at times tonight. But for the most part, it's going to be a lot easier to command than the bigger curveball.”

The addition of Bubic’s slider can help keep him unpredictable and help his other pitches play up. On Tuesday, his fastball saw an increase in velocity -- he maxed out at 95.7 mph -- and spin.

“They are a really good-hitting team, a really good fastball-hitting team,” Duffy said. “A lot of guys in that lineup like to jump heaters, so the fact that they struggled with it is a really good sign. … He threw better than a loss.”