Prior has yet to throw in a Cactus League game, and the Cubs were hoping that he would be ready on March 21, but this setback likely will cancel those plans.
The star Cubs pitcher said that before a throwing session last Tuesday, he had no arm pain and was set back two weeks during the offseason because of an illness. He made just one exhibition appearance in the past two Cactus League seasons because of elbow problems.
The Cubs had hoped Prior would be able to make a regular-season start on April 5 against Cincinnati if he made three Cactus League starts. That appears in jeopardy as well.