The Pirates acquired him from the Yankees after the 1945 minor-league campaign. In his rookie 1946 season, Bahr worked in 27 games, with 14 starts, and posted an 8–6 won–lost record, seven complete games, and a staff-best 2.63 earned run average in 136 innings pitched. But he was ineffective in 1947, was sent to Triple-A Portland after July 4, and spent the remainder of his career in the minors, retiring after the 1950 season.
The Pirates acquired pitcher Bahr from the Yankees following their minor league campaign in 1945. In his rookie year of 1946, he pitched in 27 games with 14 starts, achieving an 8-6 record, seven complete games, and a staff-best ERA of 2.63 over 136 innings. However, he struggled in 1947 and was sent to Triple-A Portland after July 4th. He spent the rest of his career in minor leagues before retiring in 1950.