At this point, Fister said, they're working to get rid of whatever soreness remains before trying again to get him throwing.
Fister took a major step forward when he threw off the bullpen mound in Kansas City on Monday. He tried to do it again Tuesday, but felt discomfort around his side.
"I felt terrific warming up and long-tossing," he said.
Fister is eligible to come off the 15-day disabled list in time for the start of the next series against Seattle beginning next Tuesday. His spot in the Tigers' rotation, currently filled by Adam Wilk, comes up in the second game of that series next Wednesday. He admitted to being frustrated, but said he's trying to make the best of it.
"It's always frustrating," Fister said, "but I've just got to take it in stride."