Robin Roberts
"Good Morning America" co-anchor Robin Roberts is a breast cancer survivor,. She has also fought a rare blood disorder known as myelodysplastic syndrome. Wikipedia

Robin Roberts, "Good Morning America" co-anchor, announced Wednesday she will take a break from the show due to her blood and bone marrow disease, Reuters reported. The 51-year-old Roberts explained that she was "not feeling well" and needed to "get some vacay" time in before her bone marrow transplant.

Last week she told a Television Critics Association panel she would be absent from "GMA" due to a planned medical leave in the fall for her procedure, Reuters said.

Roberts said Katie Couric, Diane Sawyer, Barbara Walters and other women who participate on "The View" would help co-anchor on "GMA" while she undergoes her bone-marrow transplant.

"We have so many people who love Robin so much that everyone is willing to come and join us for a bit," Tom Cibrowski, the executive producer of "GMA" said, according to Reuters.

It could take Roberts four months to recover, TMZ reported.

"I am getting ready for the bone marrow treatment that will take place," Roberts told journalists in Beverly Hills via satellite on Thursday. "We are still not sure when that medical leave will start, most likely end August, beginning September."

During the interview Roberts added that she felt "moments of fatigue" while on air.

Roberts has been facing illnesses for the past five years, Reuters reported. The "GMA" co-anchor announced in June that she had the rare blood disease myelodysplastic syndrome, or MDS, and five years ago she survived breast cancer.

When announcing that she had MDS she said, "My doctors tell me I'm going to beat this - and I know it's true."

"Myelodysplastic syndromes are a group of diseases that affect the bone marrow and blood. Some types of MDS are mild and easily managed, while other types are severe and life-threatening. Mild MDS can grow more severe over time. It can also develop into a fast-growing, severe leukemia called acute myelogenous leukemia," Marrow.org says.

The symptoms of MDS vary in severity and most people don't have any symptoms when they are diagnosed, the website said. The disease is typically discovered through routine blood testing.

Marrow.org lists such treatment options as supportive care, chemotherapy, bone marrow or cord blood transplant and "newer drug therapies." FDA has approved the drugs azacitidine, decitabine and lenalidomide for treatment.

TMZ was told that Roberts was in "good physical shape" and since the condition was found early she should be back to "GMA" before the four-month estimate.