Votto, a 24-year-old rookie, will be eligible to return on Tuesday, when the Reds travel to Pittsburgh for three games with the Pirates. Votto must be returned to the team's 25-man roster by next Saturday.
To open a spot for Rosales, the Reds designated right-hander Marcus McBeth for assignment.
With Votto unavailable, the Reds needed to add a position player. They had already been playing short-handed because of the hamstring injury that had idled Jerry Hairston Jr., who hasn't been able to play in the field.
Manager Dusty Baker wasn't sure when Hairston might return, but Baker did say he'd need to make a decision on whether to put Hairston on the 15-day disabled list at some point in the next three days.
In bringing in Rosales, Baker is getting a 25-year-old player who made an impression in Spring Training, when he hit .310. But he didn't make the Major League roster from there, going instead to Triple-A.
"He started real slow this year," Baker said. "But he's come on great."
The versatile Rosales can play all four infield positions, and in 112 games for the Bats, he had hit .281 with 10 homers and 53 RBIs. He'll wear No. 60.
Rosales will become the sixth Reds player to make his Major League debut this season. The others are right-hander Johnny Cueto, infielder Paul Janish, outfielder Jay Bruce, left-hander Daniel Ray Herrera and right-hander Daryl Thompson.
Justice B. Hill is a senior writer for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.