Peterson (5-2) took the loss Tuesday in Atlanta, allowing two runs on two hits and three walks while striking out nine in 5.1 innings.
Peterson cruised through the first five innings, holding Atlanta scoreless and allowing just a hit and two walks. After striking out Ronald Acuna to begin the sixth, he issued a walk and gave up a two-run homer to Matt Olson and was removed from the game. Over his last two starts, the lefty has fanned 16 and walked eight in nine innings of work. If Peterson starts again before the All-Star break, it would be Sunday against the Cubs.