Roberts announced in June that she has been diagnosed with bone marrow disease myelodysplastic syndrome (MDS) and will undergo a marrow transplant this year.
The journalist promised to remain on the air as long as possible in the run-up to her surgery, but will be taking time off to recover after the procedure.
Good Morning America producers have reportedly made a decision to approach a series of A-list hosts to fill-in for Roberts, an insider told TMZ.
The View's Barbara Walters and former GMA hosts Diane Sawyer, Connie Chung, Charlie Gibson and Joan Lunden are apparently among those who are being courted.
Producers reportedly want each guest host to appear for a week, with new hosts announced every Friday.
Roberts is expected to be off Good Morning America for four months, but she could return sooner based on her recovery.
She has been Good Morning America's anchor since 2005.
Roberts thanked GMA viewers for their "comfort and support" in the wake of her diagnosis last month.