McNally held the Yankees to two runs over innings on April 16, 1966, in a 7–2 victory over the Yankees. On July 21, he was one out away from a complete game against the Detroit Tigers, but with the Orioles leading 6–2, Davey Johnson made an error, allowing a third run to score. When Don Wert followed with a run-scoring double, manager Hank Bauer replaced McNally with Eddie Fisher. McNally was credited with allowing four runs (two earned), but he still got the win as the Orioles held on and won 6–4. McNally had a 10–3 record through the end of July, but had an equal number of wins and losses (three) in the final two months of the season. One of those three wins was a shutout of the Senators on August 6, in a 4–0 victory. Mark Armour of the "Society for American Baseball Research" called him "the team’s most consistent starter" for 1966. In 34 games (33 starts), he had a 13–6 record, a 3.17 ERA, 158 strikeouts, 64 walks, and 212 hits allowed in 213 innings. As a hitter, he kept his average close to .250 by midseason (uncharacteristically high for a pitcher) and finished the year hitting .195. When asked about his hitting midseason, he said, "I don’t have to explain my hitting. I mean, did Ted Williams have to explain?"