Isaiah Washington, who played Dr. Preston Burke on "Grey's Anatomy," has announced his retirement from acting. In a tweet, he cited ongoing criticism of his character as a reason for his decision, stating that he is no longer interested in the back and forth regarding a "color construct" that keeps human beings divided. He also expressed disinterest in politics or anything vitriolic. Washington was fired from "Grey's Anatomy" ahead of the show's fourth season in 2007 after using a homophobic slur against co-star T.R. Knight. He later apologized and returned for a final appearance during the show's 10th season.