MIAMI -- Ranger Suárez always knew he would need to develop a breaking pitch if he was going to make a successful transition from the Phillies’ bullpen to the starting rotation.

But like everything Suárez has done this season, it has happened more quickly and matter-of-factly than anybody thought.

Suárez, who will start here Saturday night against the Marlins, threw a grand total of 13 sliders in his first five starts after entering the rotation last month. Then, last Sunday, the lefty broke out 13 sliders, including nine against right-handed hitters, and recorded three strikeouts with it in 5 1/3 innings against the Arizona Diamondbacks.

“I have always thrown the slider. It was never a plus-pitch for me,” Suárez said Friday through a team interpreter. “But now I feel that it is.”

Just like that?

Suárez said he spent several weeks “practicing” the slider in throwing sessions on flat ground and in the bullpen, especially after Arizona feasted on his fastball-changeup predictability two starts ago. But he explained that throwing an effective slider is more than merely getting a feel for the pitch. He said he must have as much confidence to throw it in pivotal situations as he does with his other two pitches.

That doesn’t seem like an easy thing to do in the thick of a playoff race. Most pitchers use the offseason or spring training to incorporate a new pitch. But there was Suárez, throwing a slider in the dirt to strike out Arizona’s Christian Walker in the fourth inning of a one-run game last Sunday at Citizens Bank Park.

“Honestly, it’s about confidence,” said Suárez, who has a 1.48 ERA overall and a 2.03 mark in six starts. “Let’s talk about a hypothetical game situation: If I throw a slider and they hit a home run on a slider, I’m not going to make a big deal out of it. Because the way I see things is, well, maybe if I had thrown the changeup, they would’ve hit it out, too. To me, if they hit it out, it’s because they were supposed to hit a home run. And if I have to throw the pitch again, I’ll throw it again.”

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If you can’t tell, Suárez oozes confidence, more than you would expect from a 26-year-old with nine career major league starts who missed last season because of COVID-19, arrived late to spring training due to visa problems, and began the season at the Phillies’ alternate training site.

But Bryce Harper has noted his “no heartbeat” demeanor on the mound, while other teammates, including veteran reliever Archie Bradley, marveled at his ability to pitch in most any role, from long relief when he got called up in April to closing in the middle of the season, and now starting.

So when Suárez says he would have believed a year ago that he could be pitching every fifth day for the Phillies down the stretch with a postseason berth on the line, well, you actually believe him.

“I set myself really high standards and I have a very positive mindset,” Suárez said. “I want to be in this situation, helping the team make the playoffs, win important games. That’s what it’s all about.”

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Wheels up ... Monday

In a move that serves multiple purposes, the Phillies will start Zack Wheeler on Monday in Milwaukee rather than Sunday against the Marlins.

Wheeler, who has thrown more innings (182 2/3) than any pitcher in the majors, has a 6.41 ERA in his last four starts and may benefit from extra rest. But pushing him back by one day also lines him up to start twice in the last week of the season: Sept. 28 in Atlanta and Oct. 3, the final game of the season against the Marlins.

Lefty Matt Moore, who was scheduled to start Monday, will instead be available out of the bullpen. The Phillies will divide the innings among several relievers Sunday. Moore could re-enter the rotation next week. But he has allowed 11 runs on 16 hits, including three home runs, and 11 walks in 11 2/3 innings over his last three starts.

Vince Velasquez, who has been on the injured list with a blister on his right middle finger, continues to pitch on a minor league rehab assignment at triple-A Lehigh Valley. He threw 44 pitches and allowed one run in three innings Thursday night. He likely will make at least one more start before rejoining the Phillies.

“The world that we live in, you can never have too many starters,” manager Joe Girardi said. “So, we’ll try to build him back up.”

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Extra bases

The Phillies scratched Ronald Torreyes for an undisclosed reason and replaced him at third base with Freddy Galvis, who was slated to play shortstop. Didi Gregorius, reinstated from the restricted list after traveling to Curaçao for the birth of his child, played shortstop. Torreyes entered at third base as part of a double switch in the sixth inning. ... Outfielder Travis Jankowski also returned from the paternity list. ... The Phillies created spots for Gregorius and Jankowski by sending infielder Nick Maton and outfielder Jorge Bonifacio to triple A. ... Suárez will face Marlins rookie lefty Trevor Rogers (7-6, 2.45 ERA), who has allowed four runs in 18 1/3 innings in two starts against the Phillies this season.