Harang said he is confident he will have enough time to get ready for the 2015 season.
"It's frustrating, but it's not as frustrating as if this was later in camp," he said afterward. "I don't view this as any type of setback. I can progress through and catch up with my innings pretty easily. It's not that hard. I know exactly what I need to do."
Harang missed his first start this spring because of "lower back discomfort." Harang then missed Saturday's start in Lakeland, Fla., against the Tigers, because of a spasm around the middle of his back.
"This was just muscular," he said. "I woke up the other morning and just kind of moved around and grabbed on me for a second. It's being precautious. There's no reason to push this because you don't want it to linger."
Todd Zolecki is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.