MIAMI -- During his playing days in high school, Trevor Richards was introduced to the pitch that has launched him to the big leagues. 

Richards first learned to throw his signature pitch -- a circle changeup -- as a student at Mater Dei High School in Breese, Ill. Now in his second season with the Marlins, Richards’ changeup ranks among the best in the big leagues, according to advanced metrics.

Per Statcast, counting 2018 and his first start of this season, Richards has the third most strikeouts on changeups. He also ranks third in swinging strikes on the tantalizing pitch that resembles a fastball out of the hand, only to sputter drastically as it gets closer to the plate.

“It’s been a combination of coaches telling me different things and I kind of morphed it together to what felt right for me,” Richards said of how he learned his changeup.

Richards made his first start of the season on Friday in a 6-1 loss to the Rockies at Marlins Park. The 25-year-old allowed one run in six innings in a no-decision. Three of the four batters he struck out came on changeups.

Since last year, Richards has struck out 80 with the changeup. Only Luis Castillo (112) and Kyle Hendricks (102) have fanned more batters with that pitch in that span. 

As for swinging strikes, Richards has racked up 190 on the changeup. Again, Castillo (207) and Hendricks (192) are the only pitchers with more since 2018.

“The really good changeups have the same arm speed as a fastball,” Marlins manager Don Mattingly said. “When you see arm speed as the ball comes out, and it has the same spin, it’s just hard to pick up. Trevor’s got a really good one. It’s just one of those that it’s always in the back of your mind.”

Richards says he is throwing a traditional circle change, but with a twist.

“I don’t have a visible circle,” he said. “My thumb is underneath the ball so you can’t really see the circle. But it is a circle change.”

Richards is a feel-good story, reaching the big leagues a year ago after previously playing for the Gateway Grizzlies in the independent Frontier League.

Richards made it through high school and college -- Drury University -- relying mostly on a low 90s fastball and the changeup.

This year, he has scrapped his slider, replacing it with a curveball. And he’s mixing in a cut fastball. Statcast has been reading his curveball as a slider. 

On Friday, Richards threw 30 four-seam fastballs, 28 changeups and 23 sliders (curveballs).

“Just to keep hitters off-balance, that’s the name of game,” Richards said. “I’m trying to throw what they’re not looking for. Just to be able to keep them off-balance. I don’t have the power stuff. I don’t have 95-plus. For me, I’m just trying to keep them off-balance.”

Cooper resting left calf cramp

When right fielder Garrett Cooper was lifted from Friday’s game in the seventh inning, it was for more than Mattingly going with the matchups. Cooper was replaced in right field by Rosell Herrera due to a left calf cramp.

Herrera started in right field on Saturday in the third game of the series with the Rockies. 

Mattingly is hopeful Cooper will be back on Sunday.

“He cramped up in the calf,” Mattingly said. “Today, he was still tight. We’re going to try to be careful.”

Cooper took batting practice on the field and in the cages on Saturday.