Atlanta recalled Petersen from Triple-A Gwinnet on Monday.
Petersen will take the spot on the 26-man roster vacated by Spencer Strider (hamstring), who was placed on the 15-day injured list in a corresponding move. Petersen has spent most of the season in Triple-A but did make a major-league appearance against the Rays on April 13, when he struck out one batter in two scoreless innings.