was cast without the character's race being pre-determined, keeping Rhimes's vision of diversity. The production staff began casting with the program's title character, Dr. Meredith Grey, which Rhimes said was a challenging role to cast. "I kept saying we need a girl like that girl from Moonlight Mile (2002)," said Rhimes, "and after a while, they were like, 'We think we can get that girl from Moonlight Mile." The next to be cast, Sandra Oh (Dr. Cristina Yang), was initially invited to audition for the character of Bailey, but pressed to read for the role of Cristina instead. Many actors read for the role of Dr. Derek Shepherd. Rob Lowe was offered the role, but turned it down as he had already agreed to star in another medical drama Dr. Vegas. When Patrick Dempsey read for the part, "he was just perfect," according to Rhimes. The only character developed with a racial description in mind was Dr. Miranda Bailey, who is portrayed by Chandra Wilson. Her character was first described as a tiny blonde with curly hair, but when Wilson began speaking, Rhimes reported: "[Wilson] is exactly who Miranda is." James Pickens Jr. was selected to appear as Dr. Richard Webber in the series' pilot and first season. Katherine Heigl wanted to portray Dr. Izzie Stevens as a brunette but was requested to retain her natural blonde for the part. Isaiah Washington, who portrayed Dr. Preston Burke, initially read for the role of Shepherd but was cast as Burke, because the original actor to play Burke had to withdraw. T. R. Knight signed on for the pilot as Dr. George O'Malley, expecting that the role might be short-lived, because he liked that the character was multi-faceted. Rounding out the season 1 cast was Justin Chambers as Dr. Alex Karev, a character who was not originally included in the show's pilot, but added through digital editing and additional scenes. Season 2 marked the introduction of attending doctors Mark Sloan (Eric Dane) and Callie Torres (Sara Ramirez). They were initially cast as recurring characters, but both were given star billing at the opening of season 3. Ramirez was cast after ABC executives offered them a role in the network show of their choice; Dane had previously auditioned unsuccessfully for a role in the pilot episode. Dr. Addison Montgomery (Kate Walsh) also joined the show in season 2, after making a guest appearance