Smith followed Shields with three innings in which he gave up two hits and a run, but struck out five Padres and walked none. For that, Smith earned credit for the Royals' 5-4 victory and praise from Yost.
The plan was for Smith to pitch just two innings.
"The first two were so easy that I said, 'Man, we've got to give him another one,'" Yost said. "He had all three of his pitches working today. Great downhill action on his fastball, really good changeup and a really good curve. He threw all three pitches for strikes."
Actually, Smith referred to his breaking pitches as sliders.
"Me and Sal [catcher Salvador Perez] were on a pretty good page today. We usually are," Smith said. "We were working first-pitch fastballs for the most part and I think all the strikeouts came on sliders. It's still kind of a new pitch but not really. I'm starting to get a better feel for it and throw it for strikes. I like it."
Slider or curveball, it worked.
"For me, curveballs," Yost said. "Because we had opposing hitters telling our players that it was starting over the batter's eye and then breaking down into the strike zone. So it was pretty impressive, whatever it was."
The only run off Smith stemmed from Gregorio Petit's triple that hit the left-field wall between Alex Gordon and Lorenzo Cain, who seemed to miscommunicate as to who would attempt the catch.
"I thought it was gone. It was right down the middle. He's a good hitter and did what he was supposed to do with it," Smith said.
Logan Forsythe's two-out single scored Petit but it didn't diminish the impact of Smith's effort. He's had just two outings, but he's looking as if he could challenge Bruce Chen and Luke Hochevar for the fifth starting job.
"We'll see," Yost said. "It's too early."