"He feels a lot better since he's had that," general manager Kevin Towers said.
It is the same disk that gave Arroyo problems in 2011, and doctors say he is supposed to limit his activity for the next seven to 10 days.
"They want it to calm down before he starts throwing again," Towers said. "Of course, Arroyo doesn't think it will take that long. Nothing they're concerned about. It's not a herniated disk. He did it running the other day, felt it running. It's not anything worse than he had before. [Lee] thinks as long as they hit the spot right with the epidural, he should be fine."
Towers said he did not believe that the injury means Arroyo will have to begin the regular season on the disabled list. The D-backs, though, may have to juggle their rotation alignment a bit. Arroyo had been penciled in to start one of the first games of the regular season series against the Giants starting on March 31, but the D-backs will likely push him back a bit from that.
"I mean this guy had Valley Fever and pneumonia last year and found a way to start the season with the Reds," Towers said. "There's ways we could cover it. I would say he's still going to have time to get a couple of starts before the start of the season."
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.