The Cubs called up Tim Federowicz from Triple-A Iowa to take Montero's spot.
Montero, 32, did undergo an MRI exam on his back. He was surprised it had not loosened up after he rested for four days. As a result, the DL move is intended to reduce the inflammation in his back.
"I wish I had the right answer for why it happens -- I guess it's age," Montero said. "It's something that's there, it's been there. I've been able to control it and do my core exercises. Sometimes I play the whole year without any problems, and sometimes it gets a little bit annoying because it's a really uncomfortable feeling.
"The good thing is it's gradually getting better," Montero said. "I decided to tell the trainers that maybe it's better if I go on the [DL]. It's already been four days on the DL. For another 10 days, it'll be better for me, better for the team."
David Ross, 39, was to catch Jake Arrieta on Thursday, and Ross will be matched up with Jon Lester on Friday afternoon against the Braves. Federowicz would likely catch John Lackey on Saturday.
Montero was on the disabled list in 2013 because of back problems.
"It was really bad then," Montero said. "I couldn't even walk. They had to take me in a wheelchair to my car."
Cubs manager Joe Maddon said he could tell just by talking to Montero that the catcher was in pain.
Carrie Muskat has covered the Cubs since 1987, and for MLB.com since 2001. She writes a blog, Muskat Ramblings. You can follow her on Twitter @CarrieMuskat and listen to her podcast. This story was not subject to the approval of Major League Baseball or its clubs.