 After film director John Badham learned that Ross was going to play the part of Dorothy , he decided not to direct the film , and Cohen replaced him with Sidney Lumet . Of his decision not to direct The Wiz , John Badham recalled telling Cohen that he thought Ross was " a wonderful singer . She 's a terrific actress and a great dancer , but she 's not this character . She 's not the little six @-@ year @-@ old girl Dorothy in The Wizard of Oz . " Though 20th Century Fox had financially backed the stage musical , they ended up exercising their first refusal rights to the film production , which gave Universal an opening to finance the film . Initially , Universal was so excited about the film 's prospects that they did not set a budget for production . 
