Originally signed by the Yankees, lefthander Niemann came to Houston in the deal that sent Cliff Johnson to New York. He had his debut in 1979 and pitched a second season in 1980. Combined, he was 3-3 with two saves and a 4.32 ERA.

He was traded to Pittsburgh in 1981 in the deal for Phil Garner pitched for the Pirates, White Sox, Mets and Twins to complete his big league career. He compiled a 7-8 record overall with a 4.64 ERA and three saves.