"I'm really disappointed," Cordero said before morning workouts. "I've been waiting as long as I could to make the decision, but my shoulder just doesn't feel right."
Cordero has been battling a twinge in the back of his pitching shoulder that has limited him to throwing off flat ground instead of a mound this spring. He threw eight minutes Wednesday and said the pain was lingering.
"I'm not a fast starter in spring training, and I need to be careful," Cordero said. "I want the Dominican Republic to win as much as anybody back home, but I also want to be able to help the team."
Cordero is looking to regain his form as one of the best closers in the game. He had 49 saves and a 2.13 ERA in 2004 but slumped to 37 and 3.39 last season.
"I feel comfortable he made a decision in the best interest of his season and our season," general manager Jon Daniels said. "I know it was difficult for him."