The 22-year-old Marlins left-hander showed improvement with his command, but he felt he could have done better with pitch selection. Still, he viewed his four-inning, three-run stint against the Dodgers as a positive.
"I don't know if I'm anywhere near where I'd like to be, but after [Sunday], we're in a good spot," Miller said. "My bullpen [session] went really well last week, and I think for a majority of the game, we carried over what we did in the bullpen.
"I think, as far as mechanics go and breaking down the strikes, I'd say, yeah, this is a step in the right direction. I think if I make a couple of pitches, there are not three runs on the board."
A former first-round Draft pick by the Tigers, Miller has top-of-the-rotation talent. But he's not a fully polished performer, and at age 22, he is battling to win a spot on the Marlins' Opening Day roster.
"He did a lot better," manager Fredi Gonzalez said. "There is a lot of talent there. We saw some good stuff out of him."
In terms of pure ability, Miller may be the most talented of all Florida's starters. Yet, he is young and still refining his game.
Because of two early season off-days, the Marlins are planning on going with a four-man rotation until April 13. One option the team has with Miller, should it feel he is not ready when the season begins, is to send him to either Triple-A or Double-A for a start or two and then insert him as the fifth starter April 13.
On Sunday, Miller had a high pitch count, 77, and exited with one walk and one hit batter. Finding the strike zone has been an issue. He walked three in his previous start, also four innings against the Dodgers. And in his second Grapefruit League outing, he issued five free passes in three innings.
"Twenty pitches an inning isn't really a good number to strive for," he said of his average pitches.
The biggest scare Miller had on Sunday came against the first batter he faced. Dodgers left fielder Juan Pierre opened the first inning with a comeback liner that hit the heel of his right hand.
Miller's glove popped off, but the startled lefty stayed with the ball and recorded the out. He was immediately looked at by the staff and trainer Sean Cunningham but remained in the game and battled through his third straight four-inning outing.
"I didn't have time to react, " he said. "I didn't get the glove there. I still got the out, which is the important thing."
Joe Frisaro is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.