"My last tweet for awhile. Heading to hospital...time to focus on healing," she wrote. "I take each & every one of you w/me in my heart. Light and love."
Roberts, a 51-year-old breast cancer survivor, is undergoing the procedure as treatment for a rare blood disorder.
She left "GMA" on medical leave Aug. 30, then traveled to Mississippi that day to see her ailing mother Lucimarian Tolliver Roberts, who died shortly after she arrived. The elder Roberts was 88.