Lyles (side) threw a successful four-inning simulated game Monday, John Perrotto of DKPittsburghSports.com reports.
Lyles, who was removed from his previous Grapefruit League appearance due to a side cramp, fired 60 pitches in Monday's session and reported no issues afterwards. Assuming he checks out OK in the coming days, Lyles could rejoin the rotation later in the week. He's the leading candidate to open the season as the Pirates' fifth starter.