Both Maurer and Milone shut down opposing hitters through the first two frames. Millone used solid command of his breaking and offspeed pitches to keep the Mariners off balance, while Maurer simply pounded the strike zone, working out of a first-and-third, none-out jam in the bottom of the first.
"Usually my changeup is there all the time," Milone said. "My curveball has progressed a lot quicker than I expected. It's really a hit-or-miss pitch for me. I'm really surprised, but relieved that it's been able to come up so quickly."
The Mariners opted to send the bulk of their starters to Surprise, Ariz. for a matchup against the Royals, but they did have designated hitter Kendrys Morales on hand, and he went 2-for-4. Catcher Mike Zunino, the club's top prospect, also traveled to Phoenix Municipal Stadium, and he finished 1-for-3.
For the A's, left-hander Hideki Okajima, a non-roster invitee in the hunt for a bullpen spot, pitched a scoreless fourth, allowing Morales' single and a walk. He has yet to allow a run in four innings this spring.
Oakland broke the game open in the fourth, scoring three times off Mariners prospect James Paxton. The A's rallied for three hits and two walks in the frame, before Paxton was chased after recording just two outs.
Jed Lowrie added a two-run homer in the fifth to give Oakland a 6-0 cushion. Oakland's Andy Parrino and Seattle's Robert Andino traded solo homers later on.
Up next for Mariners: Right-hander Hector Noesi gets the start against the A's on Friday in a 12:05 p.m. PT game at Peoria Stadium. Noesi will be making his fourth Cactus League appearance and second start, having given up 11 hits and eight runs (six earned) in 3 2/3 innings. Noesi is a long shot for the rotation this spring after a difficult 2012 season. He's expected to throw two innings, followed by veteran right-hander Kameron Loe, who is competing for a bullpen role as a non-roster invite. Center fielder Franklin Gutierrez, second baseman Dustin Ackley and shortstop Brendan Ryan are expected back after getting Thursday's split-squad day off.
AJ Cassavell is a reporter for MLB.com. Follow him on Twitter @ajcassavell. This story was not subject to the approval of Major League Baseball or its clubs.