And no one was more pleased than the pitching coach who has been with Greinke through most of his ups and downs, Bob McClure.
"I'm very excited for him. He's come such a long way, for a number of reasons," McClure said. "[General manager Dayton Moore] brought in a class of teammates that has really helped Zack feel more a part of a team. They're more his age, and it's just more comfortable -- they have a really good relationship. And to see him grow as a pitcher, to see him grow as a man has really been exciting, because I'm seeing him enjoy what he's doing. And this is still a game and, even though it's competitive and our goal is to win a championship, part of what you've been able to do is enjoy the competition."
That's something that Greinke wasn't doing when he left the club in Spring Training 2006, McClure's first year with the Royals. Greinke went home to Orlando, Fla., to sort things out and overcome a social anxiety condition.
"I don't know how much the social anxiety had to do with it," McClure said. "He just wasn't comfortable as far as what was expected of him -- so much was expected of him and that's hard to live up to. You grow into being real good. There are very few players who come to the Major Leagues and are good right out of the chute -- it takes a lot to grow. He's in a good frame of mind, he's right where he should be because of his stuff, and we're starting to see the results of his talent. And he's enjoying it. The thing that makes me smile the most is he's enjoying the game."
Encouraged by then-manager Buddy Bell, Greinke made it back and worked much of the 2007 season in the Royals' bullpen before he was ready to resume starting. He found baseball was fun again.
"I'm sure Buddy's smiling now, too, because I think Buddy had a lot to do with putting Zack back in the right frame of mind -- putting him into the bullpen, getting him comfortable out there," McClure said. "Dayton had David Riske, who was a great combo for Zack -- they had a great relationship. It made it fun for him again, and I think that was the start of Zack enjoying the game again."
And now Greinke heads for Tuesday night's game in St. Louis with his fiancé, Emily, his parents and brother, her parents and her brother and his wife. Gee, hope he's able to get enough tickets.
"Hopefully, if not, it's too bad," Greinke said. "My mom and dad will be first on the list."
He'll also be in the company of Royals manager Trey Hillman, who'll serve as an American League coach. And his prize pitcher has a good chance of being the starting pitcher for the Junior Circuit.
Has Greinke heard anything more about that?
"I've been asked that about five billion times, and I haven't done one thing to try to figure it out," Greinke said.
Well, why should he?
"So I could answer the question faster," Greinke said. "Instead of saying, 'I don't know,' and then explain why I don't know."
There's no doubt that he'd like to start the Midsummer Classic, however.
"If I had to pick where I pitch, I'd probably pick first," Greinke said.
And, of course, if he is AL manager Joe Maddon's choice, there'll be the inevitable meet-the-press conference for the usually low-key, sometimes whimsical and often blunt Greinke.
"I probably won't have anything interesting to say, so it might be a short press conference," Greinke said.
Maybe, maybe not. There's a lot to talk about when it comes to Greinke.
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.