Obviously this move is temporary, as Gwinnett only has three games left, so it's pretty likely the Braves just want him to get the greatest number of at-bats possible before he rejoins the team. Just a pinch hit opportunity here or there may not be enough to help him work through any issues with his swing.
Gattis, 27, was one of the feel-good stories of the season back in April, when he put on a huge power display filling in for the injured Brian McCann. He has struggled the past several months, however, as he's hitting just .200 with one home run since June 10 (107 plate appearances).
In three games, he'll likely be able to see at least 12 plate appearances in Triple-A before heading back to Atlanta. The Braves are obviously hoping that's enough to help him rediscover his early-season form and become one of the most feared bench players in the league.