Peterson is slated to start Thursday's game against Toronto at Wrigley Field, Jared Wyllys of AllCHGO.com reports.
Though trade-deadline pickups Kevin Gausman and Clay Holmes (fibula) are slated to make their first starts for the Cubs this weekend, Peterson will keep his spot in the rotation for now. The left-hander tied his season high with eight strikeouts in his most recent start last Saturday against the Yankees and owns a 4.36 ERA, 1.12 WHIP and 22:10 K:BB in 33 innings over his first six starts with the Cubs since being acquired from the Mets on June 25.