Peterson will start Wednesday's game against the Nationals, Andrew Tredinnick of The Bergen Record reports.
The left-hander worked out of the bullpen in his past two appearances -- including one in bulk relief -- but will return to the rotation Wednesday after allowing just one run across seven innings as a reliever. It's been an up-and-down campaign for Peterson, who fired 5.1 scoreless frames in his season debut but followed up with an 8.79 ERA in his next three starts.