In the lead up to the All-Star break, Brent Strom noticed that Zac Gallen wasn’t getting batters off balance, as he had in his near-unhittable start to the season. So Strom, the Diamondbacks pitching coach, dug into the memories formed through his five decades in baseball.

“I took a page out of (Greg) Maddux,” Strom said, invoking the first ballot Hall of Famer, who excelled with a fastball/change-up combo. “Where instead of pressing the change-up into his glove, which kind of strengthened his grip, I kinda showed him what Maddux did where he hovers it and he doesn't really press it in there.”

The result, for Gallen, is a change-up that sits between 82 and 84 mph — roughly 10 mph slower than his fastball. Until the All-Star break, he was throwing the pitch nearly 87 mph. Although Strom noted the success of pitchers with various change-up speeds, pitching coordinator Dan Carlson considers a gap of 10 mph between a fastball and change-up to be the ideal difference.

The logic goes that at slower speeds, a change-up has more margin for error. “That way if I do make a mistake in terms of location, the speed difference might still be able to get it off the barrel,” Gallen said.

From behind the plate, catcher Jose Herrera has another explanation for why the pitch works.

“His arm speed has always been the same for all his pitches,” Herrera said last week. “But that combination into a 95-96 mph fastball with a 82 mph change-up and the way that his change-up stays on the same plane long enough and when it drops right at the end, it's really difficult to pick it up.”

Through three starts since Gallen’s adjustments, the numbers tell a more complicated story. The surface numbers in that span — 2.04 ERA, 17 strikeouts, four walks — are excellent, in part because his pitch mix is less predictable, according to manager Torey Lovullo.

But he’s only gotten three whiffs on 34 offerings of the new change-up. With the caveat of small sample size, that’s considerably lower than his season-long whiff rate of 25.8% on the pitch. Against the Guardians earlier this week, he didn’t get a single batter to swing through a change-up.

According to Strom, the problem in that outing lay in the very arm speed that Herrera praised six days earlier. Gallen, at his core, is a tinkerer. That means identifying potential improvements, but it also introduces uncertainty — a balance Strom has worked to strike with his most talented starter.

“As we tried to slow the ball down a little bit with (his grip), he took it another degree, started to slow his body down and that's what the hitters read,” Strom said. “The hitters want to dance with you and we don't want them to dance with us.”

That, though, doesn’t mean that the Diamondbacks want Gallen to discard his adjustments. As Strom notes, the Guardians swing and miss less than any team in baseball. Using them as a barometer is unfair.

Plus, Gallen himself likes the feel of the pitch. When he first broke into the majors in 2019, his change-up averaged just 85.0 mph. It was also his second best offering, according to Baseball Savant’s run value metric.

But Gallen found himself “trying to fix it.” Over the next three years, it ticked up to 87 mph. The whiff rate went down. Exit velocity went up.

So that’s where Gallen was in early July. All his other pitches felt good, but his change-up was worth negative value. Over his previous 10 starts, his ERA climbed from 1.14 to 3.56.

“(I was) feeling pretty good with the curveball, slider, cutter,” Gallen said. “So it was like, okay, let's see what we can do with the change-up.”

In his last bullpen before the break, he toyed not only with the grip Strom showed, but also a later release. “Let the hand do everything as opposed to maybe being early and trying to power it up there,” Gallen said.

Even in that first session, it felt natural. Against the Nationals in his next start, he went seven scoreless for the first time since early May. Of course, that doesn’t all come down to the change-up. The Nationals are the worst team in baseball and Gallen had an electric fastball working flawlessly.

But his pitch mix, as a whole, frustrated even Juan Soto and Josh Bell. Now, the key is finding that balance consistently.

Theo Mackie covers Arizona high school sports, the Arizona Diamondbacks and Phoenix Rising FC. He can be reached by email at theo.mackie@gannett.com and on Twitter @theo_mackie.