Peterson will start Saturday's game against the Braves, Tim Healey of Newsday reports.
The 25-year-old previously lined up to start Friday's series opener, but the Mets wanted to provided him an extra rest day. Peterson has a 4.17 ERA, 1.31 WHIP and 26:19 K:BB through 36.2 innings this season. Steven Matz is set to start Friday's contest.