The Houston Astros scratched right-hander Justin Verlander from Saturday’s start against the Detroit Tigers due to an undisclosed reason.

Rookie right-hander Spencer Arrighetti (3-5, 5.33 ERA), who was scheduled to pitch the series finale Sunday, will start in place of Verlander (3-2, 3.95).

Verlander, 41, allowed four runs on seven hits in five innings in each of his past two starts. The former American League MVP, nine-time All-Star and three-time Cy Young Award winner missed the first three weeks of the season while recovering from an offseason shoulder injury.

Arrighetti, 24, has yet to face the Tigers in his career. He allowed one run on four hits in 5⅔ innings in a no-decision against the San Francisco Giants on Monday.