The 22-year-old Schafer won the job with an impressive showing in Florida, but he struggled through his first two months in the big leagues. He was hitting just .204 with two homers and eight RBI and already had 63 strikeouts in 167 at-bats.
"He needs to work on some stuff, get it going again," Braves manager Bobby Cox said. "He's still going to be a real good player. But he's got to go down, relax a little bit and get his hitting skills going again."
Blanco was with the Braves throughout the 2008 season, batting .251 with one homer, 38 RBI and 13 stolen bases. He started Tuesday night's game against the Chicago Cubs.
Schafer, Blanco and Josh Anderson competed for the center-field job during spring training. Schafer won it, Blanco went back to the minors and Anderson was traded to Detroit.
Schafer, who had never played above Double-A and sat out a 50-game suspension last year for violating baseball's policy on performance-enhancing drugs, homered in his first career at-bat and went deep again in the third game of the season.
But the youngster has struggled mightily since then, finally forcing the Braves to make a move to shake up their lethargic offense.
"He's got a good idea of what he needs to do, based on being up here for two months and seeing the areas that he was successful and the areas that he was not successful," general manager Frank Wren said. "We talked with him today before the left about some of the areas that we wanted him to work on, so now he's going down there with a plan to improve in those areas.
"Players will tell you when they're ready to come back. He'll come back when he makes some of those adjustments.
Blanco got off to a dismal start in Gwinnett, which he attributed to the disappointment of not making the big league club.
"I wasn't going through a slump. It was mental," he said. "I felt lost. I felt like the world left me behind. I was feeling pretty bad in the beginning. But I talked to my coaches and manager and my teammates and my family, and they all supported me. They all said, 'Man, you can do it.'"
Blanco played much better in recent weeks. He was hitting .242 with 33 runs, 16 RBI and six stolen bases for the Triple-A team in suburban Atlanta.