It was Biddle's first start with Reading since being placed on the inactive list earlier this season because he needed a mental break. He allowed four hits, two runs and four walks and struck out four in 3 2/3 innings before leaving the game.
"He was OK until then," Amaro said about the injury.
Todd Zolecki is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.