Updated

Chicago White Sox pitcher Jake Peavy will not make his scheduled start Thursday against the Texas Rangers after experiencing back spasms.

Hector Santiago, who had been slated to pitch Friday's opener of a three-game series in Kansas City, will move up a day to take Peavy's place. The White Sox have yet to announce a starter for Friday's contest.

Peavy was coming off a strong month of April, having posted a 3-1 record with a 3.38 earned run average over his first five starts of the season. He allowed three runs over 6 2/3 innings to defeat Tampa Bay last Friday in his most recent outing.