"He's getting better," Yost said of Moustakas. "Right now, we're just trying to get that leg healed. We're facing tough lefties and thought we'd give him an opportunity to heal up and have him available to come into the game late or pinch-hit."
Moustakas is batting .306 (26-for-85) since the All-Star break with 13 RBIs. He'd hit just .215 previously.
"He's a valuable part of this team and he's been swinging the bat well," Yost said. "This leg injury affects him in his speed a little bit. It doesn't really affect him at third, but we want to get him healed, so we're trying to take every opportunity to give him every break we possibly can and use him against right-handed pitching right now."
Center fielder Lorenzo Cain is eligible to come off the disabled list in five days, but said he has no real timeline at this point. Cain was placed on the DL on Aug. 10 after he aggravated an oblique strain in batting practice the day before.
"It's coming along, I've been working hard, but it's very uncertain if I'll be ready in five days," Cain said.
So far, Cain has been restricted to just strength and conditioning, but he has not starting swinging the bat or throwing.
"If I can get healthy enough to run at full speed and play defense at full speed, that will be good enough for now, then I can ease my way back into hitting," Cain said.
In his absence, Jarrod Dyson and Emilio Bonifacio have been splitting games in center field.
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.