The 25-year-old Royals pitcher has captivated Cowtown with his 7-1 record, 0.60 ERA, 65 strikeouts and never-mind-the-fuss, just-give-me-the-ball attitude.
Check out the box office. For next Thursday afternoon's game at Kauffman Stadium, when Greinke will pitch against the Cleveland Indians, tickets are outselling those for Wednesday night's game by a 3-to-1 margin, according to Mark Tilson, vice president of sales and marketing.
"Thursday is real, real big," Tilson said.
It's a weekday afternoon game, too, against a last-place team. But, ah, the forecast is for a high of 85 degrees, no rain and plenty of Greinke shine.
His most recent outing was a sellout, although there were certainly other factors -- it was the always-popular Fireworks Friday and hot dogs were only a buck. Thunderstorms rolled through in the late afternoon and delayed the start of the game 2 1/2 hours. Yet the majority of the 38,353 ticket buyers stuck it out, and Greinke did not disappoint them in an 8-1 win over the Baltimore Orioles.
"I couldn't believe there were that many people here," manager Trey Hillman said. "Not only waiting out the rain for the start of the game, I was amazed there were that many people here to finish the game."
Even more telling about Greinke's drawing power, for Tilson, was the May 4 game against the Chicago White Sox. It was nice weather and upper-level tickets were just $5, but it was a Monday night and the Royals sold about 6,000 tickets that day and 6,500 more tickets after the gates opened that night.
"He was the core reason," Tilson said. "That's what people were talking about all over town."
Greinke that night pitched a shutout and ran his record to 6-0 to the delight of 21,843 fans.
By winning seven of the second-place Royals' 20 victories, Greinke has set a pace that puts him in a historical context almost every outing. For example, the latest nugget unearthed by the Elias Sports Bureau is that Greinke and Fernando Valenzuela are the only pitchers in the past 90 years to post at least seven wins with an ERA of 0.60 or less. Valenzuela was 8-0 and 0.50 to begin the 1981 season for the Los Angeles Dodgers.
That kind of magic certainly has sprinkled some can-do dust over the rest of the Royals.
"It creates such a positive environment, and everybody thrives," general manager Dayton Moore said. "There's no doubt it permeates throughout the organization."
Miguel Olivo has caught all of Greinke's games this season.
"When he goes out there and gives 100 percent, it gives the team extra energy to win games, score some runs for him and and play better," Olivo said. "He brings a lot of energy and a lot of attitude for the pitchers and the whole team."
Fellow starter Brian Bannister has felt the Greinke effect.
"It's been fun to watch, because he's pitching how we all strive to pitch right now," Bannister said. "It's exciting every time he's out there, and it's going to trickle down to the rest of the guys."
First baseman Billy Butler senses an upbeat feeling throughout the clubhouse every day.
"I don't think it's just Zack," said Butler. "I think it's everybody's mentality in here that every single day, regardless of what happened yesterday, we're going to win. I've been here almost two years now and that's something I've never felt in here before."
The fans are feeling it in the stands, too. Left fielder David DeJesus caught their fervor as Greinke pitched after Friday night's long rain delay.
"Even in the first inning, Melvin Mora with two strikes on him, the whole crowd is buzzing. And every pitch with two strikes, if it's just off the plate the whole crowd is like 'Ooooooooh!' " DeJesus said. "So you can see the crowd's in the game and it makes us, as infielders and outfielders, more attentive and you want to make a play for him."
There's a certain stamp of credibility that Greinke helps give a team, especially one that's been down for a while like the Royals. At least that's the way that third baseman Mark Teahen envisions other teams thinking: "Yeah, they've got that guy who's completely dominant and they've got a pretty nice team around him, too. So I think he just legitimizes us in some way."
DeJesus has heard another comment from opposing players: "What's he throwing? An invisi-ball this year?' "
The Orioles' Gregg Zaun was certainly impressed by Greinke, but the veteran catcher added a wait-and-see note.
"It's a tremendous start of the season for him," Zaun said. "I'm not skeptical, I've always known the kid had great stuff. But out of respect for some of the great ones I've caught, I'll wait to jump on the wagon until I see a guy do it a couple years straight. Guys like [Roy] Halladay that I've caught or [Kevin] Brown or [Mike] Mussina and the other great ones over the years. I'll just wait to see a guy put it together and keep it together for a while, because anybody can have a great month and anybody can have one great season, so I'll wait and see. But of the guys who I could pick to be a dominant force in this league for quite some time, he'd definitely be one of them."
Indeed, at the moment Greinke is one victory behind Toronto's Halladay, who is 8-1.
Greinke doesn't care much for all the hoopla, the magazine covers, the interviews. The day after his last victory, cameras and microphones from Action News and Channel 9 managed to corner him at his locker.
TV REPORTER: "Are you starting to think you can do this every time out?"
GREINKE: "No, I won't be able to do that every single time out. I mean, I can pitch how I'm pitching, but some balls will fall and some runs will score instead of spreading it out so much. It won't look as good, but I'll probably be pitching the same. Luck's not on your side all year long."
So Greinke is trying to keep things in a reality mode, and Mike Swanson, the Royals' vice president of communications and broadcasting, is helping the hurler keep his focus on pitching. Swanson had the same challenge when he was with the Arizona Diamondbacks during Randy Johnson's big seasons.
"Every time Randy got the ball, you expected something exciting to happen. You just knew something special would happen, and Zack's the same way," Swanson said. "They're completely different individuals, but they approach it the same way -- just next opponent, next pitch. They cared nothing about the accolades."
Swanson, on the field during batting practice, nodded to the pitching mound.
"Randy and Zack -- that's their sanctuary right there -- that bump," he said.
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.