PHOENIX — When Spencer Strider began to rehab after Tommy John surgery in college, he worked with Cory Shaffer, who is Clemson’s sport psychologist. Strider wanted to accomplish a lot during his rehab, from revamping his mechanics to changing his pitch arsenal.

That is where his change-up, which he flashed in his first career start, was born.

But it’s also when Strider learned an important lesson: Whereas you might think that the bulk of work to perfect a new pitch comes on the mound, it’s actually the opposite. It occurs before even trying to throw that pitch.

“I knew exactly what I wanted it to look like, what I wanted it to feel like,” Strider said Tuesday. “I learned how having that direction or focus, even when you can’t actively work on it – how far that goes. Grounding the skill or whatever is what you’re trying to achieve.”

Before he began even working on the pitch, Strider outlined what he wanted from it. He asked himself: What do I want the metrics to be? How do I want the pitch to feel? What do I want it to look like, within reason?

He said having this clear and detailed idea of this new offering – before even throwing it – “goes ahead and sets my mind and my body into what I’m trying to achieve, rather than getting on the mound and just kind of feeling it out and searching.” And if you’re searching, he added, nothing will stick.

“That’s why I think that I’m not super surprised that I was able to throw it well (Monday), just because that’s all I worked on, and I was very purposeful about developing it,” Strider said. “When you do that, you have that process behind things. It tends to stick because you establish it more, and it’s grounded in something far more deep than just one day. You feel something and you find something. That stuff tends to fall apart a lot easier.”

In Monday’s start, the first of his MLB career, Strider allowed five earned runs over 4 ⅓ innings. This line, however, is criminal. His defense let him down, and he pitched much better than the box score indicated.

Strider threw 16 change-ups in that outing. The pitch got eight swings, and four of those were swings and misses. The Diamondbacks put two of Strider’s change-ups in play, but the average exit velocity on those was only 72 mph.

This season, Strider has hurled 25 change-ups. Opponents have not yet collected a hit against that pitch.

Strider is a flamethrower whose fastball averages 99 mph. He regularly hits triple digits. This is why his slider and change-up are so important. If those pitches are working, hitters will be uncomfortable and off-balance.

Strider’s change-up averages 88 mph. “Even if the movement isn’t great, per se, for a change-up, the speed difference is still really big, so that helps me out,” he said. The pitch succeeded Monday, and Strider will look to use it going forward.

Strider is scheduled to make his second start on Saturday in Colorado.

“He’s handled everything we’ve thrown at him, and more,” Braves manager Brian Snitker said following Monday’s game. “I’ve been so impressed with this young man.”

Ronald Acuña sits out due to soreness

Ronald Acuña did not play Wednesday. He felt general soreness after playing in right field on Tuesday, which marked his first game on an artificial surface since tearing his ACL last summer.

“We’re just going to evaluate him every day,” Snitker said.

Snitker said Acuña was available off the bench if necessary on Wednesday. He hopes Acuña can play in right field on Thursday at Coors Field, which features natural grass.

Coors Field has a vast outfield. Having Acuña in the lineup would maximize the Braves’ outfield defense.

Matt Olson trusting himself

First baseman Matt Olson appears to be coming around.

Since May 18, he is 15-for-49 with nine doubles, two home runs and six RBIs. He leads the majors with 23 doubles.

In Tuesday’s loss, Olson went 4-for-4 with two doubles and a home run.

“I’m actually just trying to do less mechanically,” Olson said. “I felt like sometimes I got a little tied up in that. Just wanted to take some attention out and trust myself, and felt better.”

Olson went 0-for-4 in Wednesday’s win, but drew a bases-loaded walk in the ninth to give the club a six-run lead.

Late-game woes

In Tuesday’s loss, an ugly one, Arizona outscored the Braves by four runs following the fifth inning.

This season, the Braves have been outscored 113-84 from the sixth inning and on. That minus-29 run differential in these frames is the worst in baseball.

In 2021, the Braves were plus-46 in those innings, the seventh-best mark in the majors.