PHOENIX -- Eighteen years and one day have passed since Zack Greinke’s MLB debut, and the 38-year-old right-hander remains working hard at his craft. He is constantly evolving his game, making the necessary tweaks to his arsenal of pitches in order to enjoy continued success.

Players, coaches and managers around the league have long raved about how impressive it is to watch Greinke. Not only during his outings, but when he’s putting in his work between starts -- that’s when his vast knowledge of baseball really comes out to those around him.

“You kind of hear urban legends about him and stories and whatnot. He’s been incredible,” Royals outfielder Whit Merrifield said. “I’ve learned a lot from him, and continue to learn. I feel like I’ve kind of gotten to the point where I’m comfortable going up and talking to him. …

“He’s going to be a Hall of Famer and I’m trying to soak up every ounce of information I can from him.”

The majority of Greinke’s 19-year career has been spent with either Kansas City (eight seasons) or Arizona (four). He’s made various other stops, but those two fan bases have most gotten to see the excellence he’s capable of when he takes the mound every fifth day.

On Monday, Greinke -- now back with the Royals after 11 seasons elsewhere -- returned to one of his former home ballparks: Chase Field. It was his first time back since July 2019, when Arizona traded him to Houston. And it was also an off night for him -- a rare occurrence, even at this stage in his career. The D-backs tagged him for seven earned runs in 3 2/3 innings in their series-opening 9-5 win.

But everybody in both dugouts has seen Greinke at his best and continues to appreciate his talent.

“Zack can do anything he wants in this game,” Arizona manager Torey Lovullo said. “He is a true negotiator when he’s on the mound. He just wants to win a baseball game and get you out. And I’m sure he doesn’t care how he’s doing it.”

Greinke’s success this year has come a bit differently from when Lovullo managed the ace from 2017-19. Greinke is striking out a career-low 4.3 per nine innings, and he entered Monday with an expected batting average against of .322, the second-highest in the Majors, per Statcast.

Despite that, Greinke has mostly pitched well. His 4.53 ERA through nine starts is skewed by two outings in which he’s allowed 12 combined earned runs. He’s allowed two or fewer in six of the others.

Even on a night when Arizona scored three runs in the first -- on a pair of homers by Pavin Smith and Christian Walker -- it wasn’t a command issue for Greinke.

“I could have thrown the ball kind of wherever I wanted, just probably didn’t attack the zone enough was the issue, partially because of having the home runs the first inning,” Greinke explained. “That probably had something to do with it.”

Greinke is always learning and implementing new pitching tactics. It’s why he’s a six-time All-Star and a two-time ERA champion. So there’s plenty of reason to believe he’ll get back on track in ‘22. If not next time out, then soon.

After all, it’s what he did during his time in Arizona. He posted a 4.37 ERA during an inconsistent ‘16 season in which he was slowed by an oblique injury -- and then he recorded a 3.12 ERA in 88 starts for the D-backs from 2017-19.

“I always admire him as a true, true competitor,” Lovullo said. “He goes out there every time you give him the baseball and goes as hard as he can and wins a lot of baseball games. So I’ll never forget what he’s done for me and this organization.”

Lovullo recently became the winningest manager in D-backs history when he earned his 354th career victory on May 10. Soon after, he received a text from Greinke congratulating him on the achievement. Greinke was Arizona’s starter in 53 of Lovullo’s wins, and the two developed a great friendship during their time together in the desert.

When Greinke was still pitching in Sedona red, Lovullo told the righty that he was on a path to the Hall of Fame, and that Greinke needed to either invite the D-backs’ skipper to the induction ceremony, or at least mention him in his speech.

Before Greinke goes to Cooperstown, though, he’s not done making an impact with the Royals. After breaking into the big leagues with Kansas City from 2004-10, he returned this past offseason, signing a one-year, $13 million deal.

Sure, Greinke has put up some solid numbers so far. But that’s not the only reason the Royals wanted to get their former ace back at the top of their rotation.

Kansas City’s staff is currently filled with young pitchers who can learn from one of the all-time greats. And according to manager Mike Matheny, that type of teaching is “priceless.”

“Obviously, we always knew that these guys would get something by how he competes, but just the preparation and the understanding of his stuff, how he evaluates the opposition. I mean, all of those things are just master’s level,” Matheny said. “And you’ve got a bunch of young pitchers who are hungry to grow and have got a willing teacher. It’s a really good mix. …

“He just couldn’t be any better than what he’s been.”