He was exclusively a relief pitcher for the Yankees in the early months of 1948, posting a 2.88 ERA in 15 games and 25 innings pitched, but his contract was sold to the second-division White Sox on July 25. He finished the 1948 season in Chicago's starting rotation, and held his spot in the Pale Hose rotation in 1949 as well. In many ways, 1949 was a notable season for Gumpert.
Gumpert served as a relief pitcher for the Yankees initially in 1948, achieving a 2.88 ERA in 15 games and 25 innings pitched before his contract was transferred to the White Sox on July 25. He transitioned into Chicago's starting rotation in 1948 and maintained his position with the team in 1949, marking an important season.