Manager Andy Green confirmed Lamet will start Thursday's series finale against the Mets.
With Jered Weaver (hip) landing on the disabled list over the weekend, the Padres will turn to Lamet to fill his spot in the rotation. He's been solid in eight starts for Triple-A El Paso this season, posting a 3.23 ERA and 50:20 K:BB over 39 innings. This will mark the 24-year-old's major-league debut.