The D-backs closer has not pitched since May 28 due to tightness in his right forearm, though he was available heading into Tuesday night's game.
Qualls said he traces the injury back to pitching five times in seven days from May 19-25.
"I think prior to that, I hadn't gotten out there much," Qualls said. "I think that partially it's my fault. I should have said I needed a day off, but they needed me and I wanted to be out there. I just have to be a little smarter and know when to take a day off and give my arm a break. It's killing me not to be out there on the mound throwing."
Qualls is 12-for-14 in save opportunities with one of the blown saves being the final game of that seven-day stretch.
"I just tried to pitch through it and, obviously, that wasn't the smart thing to do," he said.
Qualls, 30, has never been on the disabled list during his career, so the forearm issue is a new one for him. Though he never ices his shoulder following appearances, he had been icing the forearm after his past couple of outings.
"The trainers all say it's in a good spot, the top of my forearm, just from overuse of my extension muscles," said Qualls, who is taking anti-inflammatory medication. "It's just overworked. They just need a little bit of time to recuperate. Just some time and some medicine should get me back out there."
Steve Gilbert is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.