"I'm very excited," said Navarro, who hit .298 with four homers and 26 RBIs in 44 games for Round Rock. "I've waited for this opportunity for a long time, and today's the day."
Navarro, 25, played in four games and went 2-for-3 in his previous Major League stint in 2006 with Seattle. He was with the Astros briefly in May but didn't record a start. He entered Saturday with no hits in five at-bats this season at the Major League level.
"I feel better and more prepared mentally and physically, and I'm happy with that," Navarro said. "I want to try to do something to help the team win."