Ka'aihue is coming off a solid game against the White Sox on Wednesday, when he had the game-winning single in the 14th inning. Ka'aihue entered the series against the Orioles batting .333. He has started nine games this season -- six at first base and three as the designated hitter -- reaching safely in seven of those games.
"He's has productive at-bats for us consistently," Melvin said. "He's hitting over .400 against lefties. So, there you go."
Daric Barton is the A's other option at first base, but he has been hampered by a shoulder injury. Melvin said Barton, who has just four hits in his past 28 at-bats, was still adjusting to the lingering effects from the injury.
"I know Bart is not swinging as well as he will," Melvin said. "I don't think the days off hurt him. I think we have two good options there [at first base]."