Tallet said he injured the muscle, which is in the area of his right rib cage, during a violent sneeze. The left-hander suffered the injury during the end of the Cardinals' last homestand, but did not notify the training staff for nearly a week.
"It just progressively didn't get any better, it got a little worse and then a little worse," Tallet said on Tuesday. "I'm the kind of guy that's going to go out there and try to battle through it until it gets to the point where they had to make a move."
The southpaw feels discomfort in his right side when he takes deep breaths and said it feels like "getting hit with a sledgehammer." Tallet will not throw for at least two days and will be able to rest during the All-Star break, which begins on July 11.
"The best thing is just to be able to get some good anti-inflammatory in there and knock out the inflammation and get it healthy," Tallet said. "You can't do that if you continually are grinding on it. I'll be able to get healed and help out the team in the second half."
The left-hander was able to pitch through the pain because the discomfort is located in his right side. But the injury limited Tallet's range of motion in his delivery. In his last outing on July 3 at Tampa Bay, Tallet gave up two earned runs in two-thirds of an inning as his ERA rose to 8.31.
"It doesn't allow me to twist and turn like I need to," Tallet said. "Everything has to work together for you to be really in sync and tuned in to throw the ball exactly where you want to. If anything's off in there, it can create bad habits and ill-advised pitches, and that's kind of where I'm at right now."
It's the second trip to the DL for Tallet this year. He was placed on the 15-day DL on July 13 with a fractured right hand.
Tallet has appeared in 18 games this season, allowing 12 earned runs on 20 hits in 13 innings.