The 36-year-old Garcia was 3-5 with a 5.77 ERA in 11 appearances for the Orioles before being assigned to Triple-A Norfolk in late June. He made 13 starts for the Tides, going 8-3 with a 2.84 ERA.
The Braves placed Garcia with their Triple-A team at Gwinnett, though he could be recalled when the rosters expand for the final month of the season.
Garcia probably wasn't going to be recalled by the Orioles in September, so they sent him to a place where he had a shot at playing in the majors.
"It was an ethical thing as much as it was an evaluation," Baltimore manager Buck Showalter said before the Orioles faced Oakland at Camden Yards. "Freddy's going to be in the big leagues for them, and we weren't sure if that's where we were going to go in September for sure. I think he deserved that opportunity.
"Now, if we're playing the Braves in the World Series and he's sticking it to us, we'll probably regret it. But in the long run, this is what's best for Freddy and his career."
Garcia has pitched for seven big league teams over a 15-year career.
Terms of the deal weren't released.