Continuing his bid to be the Royals' fifth starter, Yordano Ventura blanked the A's through four innings before exiting after giving up a one-out single to Derek Norris in the fifth.
Norris came around to score when Billy Burns drew a bases-loaded walk against reliever Donnie Joseph.
Ventura struck out six and gave up just two hits in 4 1/3 innings.
"I felt good, I felt like my pitches were working for me. I just hope I can continue to do that," Ventura said.
"He kept the ball down, used both sides of the plate with his changeup late in the count and that worked," Perez said of Ventura, who has a 2.89 ERA and nine strikeouts in 9 1/3 innings this spring.
Scott Kazmir, making his second Cactus League start, gave up a hit and a walk, while striking out three in four innings for the A's.
Kazmir worked around a leadoff error and a walk to Eric Hosmer by inducing a double-play ball off the bat of Billy Butler and a flyout from Alex Gordon.
"To be able to go in there with no outs and a couple runners on, and get out of that was big," said Kazmir, who has not given up a run in seven innings. "I wasn't particularly sharp, but a lot of my secondary pitches got me out of some jams."
Up next: Right-hander Jeremy Guthrie, who gets the 2014 home opener assignment on April 4, returns to Cactus League action against the Indians at 3:05 p.m. CT on Thursday at Goodyear Stadium. Guthrie pitched in a Minor League scrimmage in his last outing. Also on the Royals' pitching list are right-hander P.J. Walters and left-handers Justin Marks, Scott Alexander and Everett Teaford. Second baseman Omar Infante, who got a day off on Wednesday, is to return to the lineup, but shortstop Alcides Escobar will be out again with a stiff throwing shoulder. The Indians' probable starter is Zach McAllister.
Chris Gabel is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.