McNally was used as a starter through most of 1964. On May 12, he threw a shutout and allowed just two hits in a 5–0 victory over the Washington Senators. He also threw a shutout against Kansas City on June 2 in a 4–0 victory. Through August 15, he had a 7–10 record and a 3.89 ERA in 22 games, all but one of which were starts. Thereafter, he was mostly used out of the bullpen, starting just two more games the rest of the year. One of them, the second game of a September 7 doubleheader against Kansas City, was one of the shortest starts of his career; he faced four batters, all of whom scored in the Orioles' 6–1 defeat. In the other, on October 1, he threw a shutout against the Senators, throwing a no-hitter until Don Lock hit a double in the seventh inning. In 30 games (23 starts), he had a 9–11 record, a 3.67 ERA, 88 strikeouts, 51 walks, and 157 hits allowed in innings. His three shutouts tied with five other pitchers for ninth in the American League (AL).