NEW YORK—In honor of Brooklyn Dodgers legend Jackie Robinson, who broke baseball's color barrier 50 years ago last week, Major League Baseball officials announced Monday the retirement of all black players, effective immediately. "Jackie Robinson was a true pioneer and an extraordinary human being," said acting commissioner of baseball Bud Selig in a formal ceremony. "Today, we honor his memory in the greatest way possible—by making sure that no other athlete ever occupies his role as a professional black baseball player." Among the players retired Monday in Robinson's honor: Ken Griffey Jr., Barry Bonds and Frank Thomas. NHL officials said they would do the same.