Brandon Webb's troublesome shoulder could eventually require surgery. Arizona general manager Josh Byrnes said Webb was sent to Phoenix for an MRI on Friday to determine whether there are structural issues. "It's a little bit of a puzzler," Byrnes said. "We have a decent handle structurally on what's in there. ... These symptoms are related to a muscle outside the joint. They've been persistent, and we haven't been able to resolve them." If Webb does need surgery, he may have thrown his last pitch for the Diamondbacks. Arizona would likely be hesitant to pick up the 2010 option on his contract, which is worth $8.5 million.