"He's starting to swing the bat better," Yost said. "He's staying back, using his hands better, swinging better."
Even so, Ka'aihue and his .205 average did not appear for the Royals on Tuesday in their 6-5 win over the Orioles.
"The last two or three games, he's taken some pretty good swings," Yost said, "but we've got [Mike] Aviles hot, [Wilson] Betemit hot and we've got a guy in [Jeff] Francis, who gets probably the least run support on our staff and we've got to score some runs for him and get a 'W' for him. We need to get the hot guys in without losing defense up the middle with [Chris] Getz, who's swinging a little better too after his little funk."
Yost had Betemit starting at first base for the first time this season with Aviles at third and Getz at second. Betemit has played first base 63 times in his big league career including four starts at the position last year for the Royals and 39 overall.
"That's actually probably his best position," Yost said.
It's been a good position for Betemit's teams, too. When he's appeared at first base over the years, his team has has a 44-19 record.
Ka'aihue, in his last seven games, hit .320 (8-for-25). He had two doubles and one of his two homers this season.