KANSAS CITY -- It took all of one plate appearance for Edward Olivares to announce his return to the Major Leagues.

His second was just a bonus.

The Royals outfielder crushed two homers in back-to-back at-bats on Friday in his first game after being reinstated from the injured list, sending the Royals to a 3-1 series-opening win over the A’s at Kauffman Stadium.

“What can you say about Oli?” manager Mike Matheny said. “Just like when he left, this guy was the at-bat we wanted to watch. Because he was just doing something every time he walked up there. Fastball, pretty good pitch, changeup too.”

In his first at-bat against lefty Cole Irvin, Olivares took a curveball for a called strike before mashing an elevated fastball 430 feet out toward the Royals Hall of Fame in left field.

“It just felt like good, good, good contact,” Olivares said with a laugh.

His second blast was a changeup down and in after Irvin had attacked away. With the way Olivares crowds the plate, he was ready for an inside pitch, hammering it 411 feet over the left-field wall.

“What I’ve seen develop into is really seeing him staying with a good approach against everything,” Matheny said. “... He’s just got the mix of the power, and mostly the hand-eye and the bat speed that allows him to cover balls on the inside part of the plate and keep them fair.”

Olivares’ first career multi-homer night backed another welcome return with Zack Greinke. In his first start since May 29, a day before hitting the injured list with a right flexor strain, the veteran right-hander twirled a quality start, allowing one run on three hits, with no walks and four strikeouts.

Greinke earned his first win as a Royal since Sept. 30, 2010 -- 4,285 days ago.

“I guess since it’s been so long, a little bit,” Greinke said when asked if this win meant any more to him than the others.

It meant a lot to Kansas City, at least. The Royals have been playing better lately, coming off a winning West Coast road trip and improving to 6-2 in their last eight games. But it’s obvious they still need the contributions of Olivares and Greinke. Olivares was just hitting his stride when he hit the injured list with a right quad strain in May. He was hitting .371/.421/.486 in 15 games and had seized everyday playing time to help get the Royals' offense going.

“Unfortunately, injuries are part of the game,” Olivares said. “Yeah, it was tough, but you just got to focus on working, keeping your head up and attacking every day. … I’ve been waiting for this day for a long time, and I’m glad I’m here, glad to contribute.”

Now that the 26-year-old is back, he should get those same opportunities. As MJ Melendez takes over primary catching duties with Salvador Perez on the injured list, right field opens up for a rotating cast: Olivares and Kyle Isbel, primarily, with Whit Merrifield and Hunter Dozier able to play there, too.

Olivares’ production will earn him the most time.

“We talk about dangerous hitters, and a lot of these young hitters we have, when they walk up there, it looks like damage is about to happen," said Matheny. "He’s just been in a good place, before he got hurt and to come back that quick and have the timing right and make an impact like that today, it’s special.”

And Greinke, the veteran starter acquired to anchor one of the youngest rotations in baseball, looked exactly that now that he feels healthy again, with a sharpness to his pitches that he lacked in his final few starts before going on the IL. He painted his fastball and generated weak contact with his cutter, a pitch he calls a slider but one that’s different from the typical breaking pitch (which he still throws).

This new pitch is harder and has a different grip, something Greinke has been working on over the last year.

“Completely different,” Greinke said. “I guess the thought is to just mix it up some, throw more pitches instead of a couple pitches.”

Greinke improved to 12-3 with a 2.70 ERA (40 earned runs in 133 1/3 innings) in 20 career starts against Oakland, holding the A’s to two runs or fewer in 15 of those 20 starts.

“He’s a very smart pitcher, especially with the way he can locate that cutter inside and outside,” A’s shortstop Elvis Andrus said. “That’s when it gets tough. He was throwing 90-92 a couple of times. He’s super smart, man. You gotta go out there and try to stay in the middle. When he’s hitting those corners, it becomes really tough to get good contact.

“But he’s been doing it his whole career.”