He pitched effectively in relief for Chicago, winning his two decisions and posting a 3.00 ERA, but that December he was traded again, this time to the Philadelphia Athletics. However, Klieman was ineffective in five  relief appearances and was sent to the minor leagues, where he finished his pro career in 1951.
He threw effectively in relief for Chicago, securing his two victories and recording a 3.00 ERA, but that December he was traded once more, this time to the Philadelphia Athletics. However, Klieman struggled in five relief appearances and was sent to the minor leagues, where he concluded his professional career in 1951.