Cole is suffering from right lat soreness after a bout with right shoulder fatigue.
He was removed from his start against the Philadelphia Phillies on Friday with the lat issue. He was making just his second start since coming off the disabled list June 28.
On Friday, Pirates manager Clint Hurdle said he didn't think anyone was "overly alarmed" about the injury. However, Cole threw in the bullpen Monday and later was scratched from his scheduled Wednesday start against the St. Louis Cardinals as the team prepared to place him on the 15-day DL.
"It's very frustrating," Cole said, according to the Pittsburgh Tribune-Review. "The bullpen just didn't go well. I wasn't myself. If you can't be yourself in a bullpen, how can you do it when you pitch (in a game)? It's hard enough to get through the Cardinals' lineup when you're feeling good."
"This risk is not worth the reward for this particular start," Hurdle told the Tribune-Review.
Cole, 23, who was the first overall selection in the 2011 draft, had been out since June 4 before returning June 28 against the New York Mets. He allowed the Mets to score five runs in four innings in a 5-3 loss.
On Friday, Cole threw just 80 pitches in five shutout innings, allowing one hit, walking one and striking out five, as the Pirates routed the Phillies 8-2. Cole picked up the win.
He is 7-4 with a 3.78 ERA in 14 starts.
The Pirates will call up right-hander Brandon Cumpton to take Cole's place in the rotation, according to media reports. He is 3-2 with a 4.61 ERA in nine starts this season for the Pirates.
Information from The Associated Press was used in this report.