An MRI performed on Span on Wednesday revealed a sprained sternoclavicular joint, which connects the clavicle to the sternum. He originally incurred the injury while trying to convert a sliding catch on Aug. 12 against Tampa Bay.
"We're going to give him this time and back away here," manager Ron Gardenhire said. "He's not getting better. Let him sit out for a few days, stay home, do some rehab, and go from there."
Span missed his third straight game on Thursday due to the injury.
The 28-year-old outfielder said on Wednesday -- before the Twins decided to place him on the DL -- the club would treat the situation accordingly with a day-to-day approach.
"I don't think there's really much I can really do," Span said. "They said it takes four to six weeks for it to heal -- if I just did nothing. But they don't seem to think me continuing to try to swing will make it worse. So hopefully get on this anti-inflammatory and get some more treatment, then maybe it'll be more bearable for me to at least play."