However, Kansas City's first-round pick in 2002, sixth overall, has his highest number of wins as a member of the Royals (60, from 2004-10).
Greinke (15-5, 2.99 ERA) will face his former team for the fifth time in his career Saturday in the second game of a three-game series. He'll be facing Kansas City lefty Mike Montgomery (3-8, 4.77 ERA).
The Astros will be going for a series win, having defeated the Royals 4-1 on Friday behind a strong eight innings by Gerrit Cole.
Greinke, the quirky right-hander who asked to be traded during the 2010 season, has never faced the Royals away from Kauffman Stadium. He's 0-2 with a 3.24 ERA in four career starts vs. Kansas City, with four different teams. He last faced the Royals in 2017 as a member of the Arizona Diamondbacks, when he allowed two earned runs in four innings in taking the loss.
If he beats the Royals, they would be the 30th opponent he's defeated in his career.
When the Royals traded Greinke to the Milwaukee Brewers in 2010, the deal brought back Lorenzo Cain and Alcides Escobar, two key members of Kansas City's back-to-back American League champions in 2014 and 2015, and two other players who were part of the trade that brought the Royals James Shields and Wade Davis prior to 2013.
His manager is excited that Greinke is with the Astros now.
"It's kind of a match made in analytical heaven," A.J. Hinch said. "He's an analytical mind and a super-prepared pitcher combined with an organization that leaves no stone unturned when it comes to trying to bring the best out of guys.
"He's blended in very, very well. I think he appreciates being added to a pitching staff that already has Justin Verlander and Cole. He just has to do his part. He's been even a little bit more interactive and upbeat and much more comfortable at a faster pace."
Montgomery also was traded away from Kansas City prior to the championship seasons -- though he won a World Series ring with the Chicago Cubs. He was reacquired by the Royals on July 15 in exchange for catcher Martin Maldonado, who was sent to the Cubs. After four games in Chicago, Maldonado was traded to the Astros.
Montgomery absorbed the loss in a 9-0 setback on Sunday in Miami, allowing a season-high-tying five runs on eight hits in four innings. It was the first time since July 30 that he failed to complete five innings.
"I feel like I've thrown the ball pretty well as of late," Montgomery said after that start. "You come on the road, it's a getaway day going up against a guy that's really good. You can't really worry about what the other guy's doing; you've got to pitch your game.
"That's baseball. Those things happen, so it's got to be short memory. Understand I did some things (well) today and couple little mistakes -- probably more mental mistakes, pitch selection. I've been able to field my position. Those things cost me today."
Montgomery last faced Houston on July 17, 2016, taking an 8-1 defeat as a member of the Cubs. He is 1-1 with a 2.29 ERA in seven outings (two starts) lifetime vs. the Astros.
--Field Level Media