"We wanted another right-handed bat on our team, and Johnny's been killing the ball in Triple-A," Yost said.
Giavotella, after a slow start for Omaha, was batting .331 (44-for-133) in 31 games. He had five homers, eight doubles, 25 RBIs and 28 runs with a .408 on-base percentage.
"Numbers-wise, I started a little slow," Giavotella said, "but I was actually swinging the bat real well. I was just hitting the ball right at people. Those things happen in baseball. Luckily over the past few weeks, balls have been falling and I've started to get hot."
Last season, Giavotella was called up on Aug. 5 and became the Royals' regular second baseman. That won't happen this time around; he'll share second base with Chris Getz.
"He'll play against left-handers and be a bat off the bench," Yost said. "We like what Getzy's doing at second base."
Hosmer, in a 1-for-16 slide and batting just .181, actually will get two days off because Thursday is an open date.
Third baseman Mike Moustakas, despite batting .311, was also out of the starting lineup, but not because he also is a left-handed hitter.
"Moose has kind of been hampered with a little hamstring soreness, so two days for him was a good time," Yost said.
Backup infielder Irving Falu was stationed at third base. With Moustakas also out of the lineup, it put six right-handed batters against Lester, including switch-hitters Falu and Brayan Pena.
Giavotella was sent to Omaha toward the end of Spring Training as Yost decided to go with Getz and Yuniesky Betancourt at second base. Betancourt is currently on the disabled list with a sprained right ankle.