"He's better," manager Ned Yost said. "I'm not going to let him swing today, but tomorrow we'll see how he feels."
Yost explained that on Callaspo's last swing in Friday night's game, the bat caught in the pine tar on his batting glove.
"What he did was he kind of pinched two bones together, so it's more of a bone bruise which has created a soreness," Yost said.
The Royals feared a strained ligament, an examination revealed no such damage.
Wilson Betemit, who made several fine plays in Saturday night's 4-2 victory, was back at third base.