"He came in looking really bad," manager Ron Washington said. "We don't need anything else in there. He came in early and no one was here. We thought it best to send him home."
The Rangers have dealt with sickness and injuries the past few weeks.
Starting pitchers Neftali Feliz, Derek Holland and Alexi Ogando, who moved from the bullpen to the rotation because of injuries in the first place, are on the disabled list. Holland lost 15 pounds in 2½ weeks because of a stomach ailment that he's finally over. Catcher Mike Napoli also dealt with illness, but has managed to play through it.
Cruz is hitting .261 this season with eight homers and 36 RBIs. But he was just 7 for 32 (.219) on the club's recent 10-game road trip in which they went 4-6.
Cruz left Saturday's game early and didn't start Sunday (but did pinch hit) because of a sore Achilles.