Per the article:
Octavio Dotel, 33, suffered a setback Thursday when he experienced renewed problems with his strained left oblique while throwing from a mound at the club’s year-round facility in Surprise, Ariz.
Plans call for Dotel to return to Kansas City to undergo a follow-up magnetic resonance imaging (MRI) examination today to determine the cause of the continuing pain.
“He was throwing well for the first 20 (pitches),” manager Buddy Bell said. “Then he felt something similar to what he had before. Same area. We’re not sure if he’s reinjured it or whether this is just part of the (recovery) process or what. We’ll have to wait and see.”