After Friday, ABC anchor Robin Roberts will officially be on medical leave from top-rated morning new program Good Morning America. Having been diagnosed with myelodysplastic syndrome or MDS, the 51-year-old veteran journalist is set to undergo bone marrow transplant surgery. As it turns out, her older sister, Sally-Ann Roberts, is a "perfect match and she’s been spending a lot of time with me.  She’s been taking shots to help her prepare." The operation will be performed early next week. The popular ABC fixture plans on resuming her role at the network and emphatically states, "I know I’m going to have a job when I come back." During her absence, ABC plans on using a roster of celebrities to fill in for Roberts. TMZ reported a while back that the list of contenders for Roberts' chair included Diane Sawyer, Charlie Gibson, Barbara Walters, Chris Cuomo, Connie Chung and Joan Lunden. The recovery time for the procedure is about four months, according to TMZ. This isn't the first health scare for Roberts. She was diagnosed with breast cancer back in 2007. She was through surgery and returned to work just 10 days later. She also underwent chemotherapy and radiation.