D-backs manager Kirk Gibson said that the team will put Demel on a strengthening program, and it is hoped that he will be able to come off the DL after 15 days.
"The doctors examined him," Gibson said. "But [they found] nothing alarming. I don't believe there's any MRIs scheduled."
Demel is 1-2 with a 1.72 ERA in 21 appearances this year, and he pitched back-to-back days eight times, including three days in a row at one point.
"He's been on and off with the shoulder," Gibson said. "I've had to watch his innings. He's been throwing the ball well, but I know the last outing he went out there, he was hurting, and that's not good at all to have him pitch that way."
With a day-night doubleheader scheduled for Tuesday, the team didn't feel it could risk being short an arm in the bullpen, so it decided to make a move.