Maholm, who was diagnosed with a left shoulder strain and placed on the disabled list retroactive to Aug. 18, said he did not want to do any more damage to the joint.
"I don't think it's anything big, but it kind of got to the point where I thought I was doing more harm to myself and the team by going out there," Maholm said.
This is the first stint on the disabled list for Maholm, who made his Major League debut in 2005.
"I've dealt with [shoulder pain] other years. It's usually gone away, and I've done pretty well," Maholm said. "This time, it just kept lingering and obviously, I don't want to just keep pitching to pitch and do anything major to it."
Maholm lasted just five innings in each of his last two outings. Since July 10, his ERA has risen from 2.96 to 3.66. Maholm said he did not think the pain had an effect on his mechanics, though.
"I'll take responsibility for every start," he said. "I'm not going to throw my shoulder into it. It's me going out there pitching.
"I've had some great starts. It's just on and off for the past little bit, where obviously, I haven't been effective. The team needs someone out there who can win games."