But unlike his previous visit to Kauffman Stadium in June, when Greinke was with the Brewers, he'll be wearing an Angels uniform as he faces his former team. The right-hander won the American League Cy Young Award pitching for the Royals.
In 109 career games at Kansas City, including 89 starts, Greinke is 36-28 with a 3.52 ERA. He'll be looking for more of the same as the Angels look to secure a series win and improve their standing in the AL Wild Card race after winning the series opener, 9-7, on Friday night.
The Angels sit 2 1/2 games back in the AL Wild Card standings -- thanks to losses by the Orioles and Yankees on Friday.
Greinke won each of his previous four starts, allowing a combined six runs in 28 2/3 innings. Last time out, he beat the Tigers with seven innings of two-run baseball, allowing five hits and a walk with seven strikeouts.
It's a welcome sign for the Angels after Greinke initially struggled after being acquired in a trade with the Brewers. He allowed four or more runs in four of his first five starts for Los Angeles. Manager Mike Scioscia credited it from gaining familiarity with his new teammates.
"Zack is feeling much more confident after a couple starts with us, and getting a little comfort level with our catchers," Scioscia said. "He's pitched terrific baseball his last handful of starts. He's well-prepared, loves to go out there and compete. We need him to make our run, that's for sure."
Also on a roll is Royals right-hander Jeremy Guthrie, who hasn't lost since Aug. 3. Greinke's opponent has won four games and earned a no-decision in three other starts since his last defeat against the Rangers.
Guthrie didn't factor in the decision last time out, a Royals win over the White Sox, but made one of his best starts of the season, throwing eight shutout innings with seven strikeouts.
Angels: Pujols back at first base
A right calf injury forced Albert Pujols into the designated hitter role for the last 16 games, but he was back at his usual spot at first base for the series opener with the Royals on Friday night.
It was his first start at the position since Aug. 22, which followed with him being on the bench for four games before becoming the DH.
"I think he's far more comfortable when he plays the field, as far as what he can contribute to the team," Scioscia said. "And if he feels good about where his leg is, if he feels he can get out there, that's definitely a plus for us."
Royals: Cain's season likely over
Royals outfielder Lorenzo Cain has a Grade 2 strain of his right hamstring and will likely not play again this season.
The injury happened Thursday night as Cain tried to chase down a double off the bat of the Twins' Alexi Casilla in the 10th inning of a 4-3 loss.
Cain is batting .266 with seven homers, 31 RBIs and 10 stolen bases in 61 games for the Royals this season.
The club recalled Jason Bourgeois from Triple-A Omaha to fill Cain's spot, and he went 2-for-3 with a run and an RBI as the leadoff hitter on Friday.
Scioscia said infielder Maicer Izturis, who is dealing with a left rib strain, could see action against the Royals in the weekend series.
Billy Butler hit his 26th home run of the season on Friday, four shy of the 30-homer milestone that hasn't been reached by a Royals player since Jermaine Dye hit 33 in 2000. It also was Butler's 100th overall.