Hellickson, 28, has pitched to a 9-8 record and a 4.60 ERA for the D-backs this season. Hellickson is 6-3 with a 3.55 ERA in 11 starts at home and 3-5 with a 5.71 mark in 12 starts on the road, and he has a 3.41 ERA in six starts since the All-Star break.
• Delgado expected to finish season in rotation
With two straight wins, Hellickson acknowledged this injury comes at a bad time, but he knows it's better to not risk making it worse by continuing to pitch.
"It's never a good time to go on the DL, especially this late in the year," Hellickson said. "I just want to be out there and take the ball every five days and help this team, but I'd rather be healthy for the last seven or eight than go out there Saturday and make it worse."
Anderson, meanwhile, was optioned to Reno following his start against the Pirates on Tuesday, but he was allowed to be recalled before the typical minimum 10 days in the Minors because he's replacing an injured player. Anderson has gone 5-5 with a 4.51 ERA in 21 starts for Arizona, but opponents have reached him for a .280 average.
D-backs manager Chip Hale said he was hoping for Anderson to get a couple of starts under his belt with Reno to work on his location, but the club needed him back up after the injury.
"The encouraging thing, and I told him this when we sent him out, he's done it," Hale said. "He was our best pitcher early on and we know he has the ability to locate better. We know he has the ability to pitch down in the zone like we've asked, so he's just going to have to do it here. Obviously, we wanted to try to give him a start or two down there, but this is baseball. That's the way it goes."
The D-backs also announced they had returned catcher Gerald Laird from his rehab assignment with Triple-A Reno, reinstated him from the 60-day DL and designated him for assignment. Laird, 35, appeared in only one game this season for Arizona, on April 8 against the Giants.