It's a strong possibility, given that both Barton and Ka'aihue are left-handed hitters, and the A's are already equipped with plenty of other bats on the bench. They'll need to recall a fifth starter next week and, when they do so, will have to make a decision on Ka'aihue, who is off to a 3-for-8 start.
Ka'aihue said on Monday that he knew he could have been the one packing his bags when Barton was reinstated from the DL and said he wasn't sure "what went into their decision," but is grateful he's still around.
"While I'm here, I'm going to continue to try to do my best," he said. "I've just been trying to make the most of my opportunity, and I feel like I've done that. I'm putting together good at-bats."
Manager Bob Melvin said Monday's decision between Allen and Ka'aihue came down to offensive performance, and he is expected to use Ka'aihue off the bench as a pinch-hitter and at first base when Barton needs to rest his shoulder.
Should the A's choose at some point to designate Ka'aihue, who is out of options, Melvin has said he is comfortable with Josh Donaldson as a backup first baseman.