SURPRISE, Ariz. -- Zack Greinke is entering his 20th MLB season. He has won a Cy Young Award, Gold Gloves, ERA titles and Silver Sluggers. He has been to six All-Star Games. He’s putting the finishing touches on a possible Hall of Fame career.

Yet he spent this offseason working harder than he ever has.

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Despite solid results in 2022 with a 3.68 ERA, Greinke wasn’t happy with his performance last year or the year before, when he had a 4.16 ERA with Houston. If that wasn’t enough for him to start thinking about adjustments being made, the rules changes implemented by MLB for 2023 were.

“The shift rules are going to be a bit tougher for some pitchers than others,” Greinke said Monday after needing 22 pitches to get through two scoreless innings in his spring debut during the Royals’ 10-4 loss to the Brewers. “Not striking guys out, it’s a little bit tougher to get guys out consistently without the shift. Felt like I had to make a couple of changes, and, hopefully, they work out.”

New rules in effect this season restore a more traditional defensive alignment to better showcase athleticism of players and produce more traditional outcomes on balls in play. Two infielders must be positioned on either side of second base when a pitch is released, and all four infielders must have both feet within the infield.

Greinke, whose 12.5% strikeout rate last year was the lowest in baseball among pitchers who threw 100 innings, said he specifically looked at his changeup when thinking about how shift restrictions could affect him. The pitch had a 72.6% ground-ball rate in ’22. Of the ground balls hit against his changeup, 41% were to the batter’s pull side and went up the middle slightly more than they were pulled (44.3%).

Having three infielders on one side of the infield helped cover both in the hole and up the middle against Greinke’s changeup: With the shift on, batters hit .200 against Greinke’s changeup (9-for-45) last year. With standard alignment, they hit .385 (15-for-39).

“My changeup gets ground balls to the pull side all the time,” Greinke said. “So when there’s only two guys over there, it’ll be a hit more often than it has in the past. I had to make some changes. If it wasn’t for that, I probably would have continued to do what I had been doing.”

Greinke, 39, went to Driveline in Arizona this offseason, something he’s never done before in the past. He worked with trainers at the data-driven facility a little on his velocity but more on pitch design and helping his pitches work better after evaluating last season and the way hitters picked up his stuff.

Greinke enjoys using data to gain insight on his pitches -- it’s part of what’s made him effective as he gets older, as well as his willingness to change.

“I like it a lot because I believe in it,” Greinke said. “All those number things. Especially because in Houston, they would call guys up that weren’t even good prospects. And they’d say, ‘This guy’s going to be good because his pitches do this.’ And the pitcher ended up being good.”

Watching Greinke figure out ways to adjust does not surprise anyone in the Royals clubhouse.

“He’s always changing stuff up,” catcher MJ Melendez said. “There were a couple of times last year where he literally invented a new pitch like right before a game. Nothing really surprises me. He’s fun to catch because he’s always around the zone, so it’s easy to be able to adjust as a catcher with anything he starts throwing.”

Melendez caught Greinke on Monday and described it as an “easy” day behind the plate. That’s because Greinke was calling his own pitches from the PitchCom device that debuted last spring. Instead of Melendez wearing the transmitter and calling for pitches, Greinke wore it on his belt. Veteran starters Max Scherzer and Adam Wainwright have both worn it this spring, too.

Greinke thinks wearing the device helps with the pitch timer -- he has so many pitches and shakes off the catcher often because he knows what he wants to throw that it’s easier to just call the pitch himself.

“It’ll be really tough to not do that with the time limit,” Greinke said. “I throw a lot of pitches and just won’t be able to throw the pitch I want a lot of times if I can’t use that. I really hope it’s allowed.”

If there’s one guarantee as Greinke begins his 20th season, it’s that it’ll be different than the previous 19 years. No one is better equipped to handle that than Greinke.

“Almost every day, I hear him or hear of him talking about changing the way his pitches move,” manager Matt Quatraro said. “He’s never satisfied. He’s a future Hall of Famer and still not satisfied? That takes a special breed for him to still want to do that.”