Deduno told the Pioneer Press on Sunday that he's been feeling pain in his throwing shoulder, and that might be to blame for his recent struggles.
"Maybe he's got a little arm fatigue," Twins assistant general manager Rob Anthony said. "The report that I got was just a little biceps tendinitis. It's not uncommon this time of year for pitchers to go through that."
The good news is that the injury doesn't sound serious.
His next start is slated for Friday at Cleveland.