"I think we feel like we've got enough depth," Towers said. "We actually considered even moving some of our depth. It's probably a good thing we didn't, for this very reason."
The Diamondbacks recently found that right-hander Daniel Hudson could be lost for the remainder of the season. The 25-year-old has undergone an MRI that showed a tear in his ulnar collateral ligament. While Hudson is seeking a second opinion, this injury usually leads to Tommy John surgery.
Arizona is also without veteran starter Joe Saunders, though Towers believes the left-hander will be back right around the All-Star break.
"I think he'll be back if not before then right after the All-Star break," Towers said. "He's feeling great. I think he must have slept on it wrong or had a little bit of a dead arm. He's responded well. The doctors said his strength tests are all good."
Along with Saunders’ pending return, another reason Towers is comfortable with the Diamondbacks current group of arms is because he has confidence that right-hander Josh Collmenter will rebound in his second chance in the rotation.
The 26-year-old struggled early on this season, though he did post an ERA and WHIP of 3.38 and 1.069 over his 31 appearances, including 24 starts, for the Diamondbacks last season.