Willie Hawkins
Willie Hawkins was a baseball player for the New York Giants in 1953. As the lone Negro on the team, he was admirerd by the people of Harlem, but to most Whites of the time, he was "just another colored man".
Willie Hawkins was part of Benjamin Sisko's visions from the Prophets and the Pah-wraiths. He had pursued Cassie, Benny Russell's wife-to-be, at some point and often hit on her, only half-jokingly. (DS9: "Far Beyond the Stars")
Background
Willie Hawkins was portrayed by Michael Dorn. Although there was no real Willie Hawkins, the character is probably based on the similarly named Willie Mays, who played for the Giants from 1951-1971 but ironically not in 1953 as he was serving in the military during the latter stages of the Korean War.
In the episode "In the Cards" from the previous season, Jake Sisko and Nog make a series of increasingly complicated trades to acquire a Willie Mays trading card for Jake's father. Thus, Mays already had an important tie to Captain Sisko, and one could reason that Sisko imagined Hawkins as an incarnation of Mays.