Royals' Jake Brentz: Throws bullpen

Brentz (hamstring) thew a bullpen session Tuesday and remains on schedule, Byron Kerr of MLB.com reports.

Brentz was placed on the 15-day injured list Thursday after suffering a Grade 2 hamstring strain in mid-March. In the bullpen session Tuesday, he threw 20-30 pitches without any apparent setbacks. Brentz may soon be ready to face live hitters, although the Royals may opt to have him attempt at least one more bullpen before progressing to that next step.