Jon Heyman of MLB Network reported the news, noting it is a minor league contract that will send the long-time San Francisco Giant to the Braves' alternate site.
According to Bleacher Report's Scott Miller, Sandoval could be eligible for Atlanta's postseason roster if that is what the team wants.
Sandoval started his career with the Giants in 2008, played for the Boston Red Sox in 2015, 2016 and part of 2017, and then returned to the Giants.
He is a two-time All-Star who helped San Francisco win three World Series titles during his time in the National League West. He was also the 2012 World Series MVP and anchored the Giants' lineup throughout much of his prime.
However, Sandoval has not been the same productive force of late.
The last time he played more than 126 games was the 2014 campaign, and he is slashing .220/.278/.268 with one home run and six RBI in 33 games this season. San Francisco, which is fighting for a playoff spot in the expanded postseason field in 2020, elected not to keep him on the roster.
The Braves are also battling for postseason positioning in first place in the National League East and will at least have the option of playing Sandoval in October following this move.
He has a history of postseason success and could help as a pinch-hitter or spot starter.