That is, of course, subject to change if the blister on Hellickson's right thumb takes longer than expected to heal.
"We're trying to maximize the rest factor here," D-backs manager Chip Hale said. "I think we have Robbie going out the first day against the Giants. We're probably trying to get Chase as much rest as we can."
The D-backs also want to break up Anderson and Hellickson in the rotation because the right-handers are similar in style.
Ray was a candidate for a rotation spot this spring, but the left-hander pitched poorly and began the year with Triple-A Reno. He has thrived since being called up while Opening Day starter Josh Collmenter, who was outstanding during the spring, struggled when the regular season began and was demoted to the bullpen.
"I think that Robbie Ray is one of the guys who's kind of the leader of the staff right now if you look at the performance," Hale said of Ray, who is 3-4 with a 2.16 ERA in eight starts. "It's really surprising after Spring Training, with the troubles he had in spring, troubles locating his fastball and the off-speed pitches being a part of his repertoire. He's come up here from Reno and really impressed. I think that's one of the good signs."
Steve Gilbert is a reporter for MLB.com. Read his blog, Inside the D-backs, and follow him on Twitter @SteveGilbertMLB. This story was not subject to the approval of Major League Baseball or its clubs.