The 1957 season was Thurman's best in the major leagues. He started the year on a hot streak. On June 1 he was hitting .351, but by the end of June his average had dropped to .259. On August 2 he was sent down to the Seattle Rainiers of the Pacific Coast League. He hit 8 home runs in the Pacific Coast League before being recalled by the Reds later in August. The Reds were in a slump, and Thurman helped get them out of it. In his first five games back with the team, he hit 4 home runs with 12 RBI. For the 1957 Reds he hit 16 home runs in 190 at bats. His home run per at-bat percentage of 8.4% was better than Duke Snider who led the league at 7.9%, although Thurman lacked the plate appearances to qualify officially.