Guettler began his career in 1945 with the Kingsport Cherokees, leading the league with 13 home runs.
[4] With the Montgomery Rebels and Gadsden Pilots in 1948, he led the league with 24 home runs.
Between Portsmouth and the Toledo Mud Hens/Charleston Senators in 1952, he hit at least 28 home runs while batting .330.
He led the Piedmont League again in home runs and RBI (104), as well as batting average (.334).
[4][6] He was a mid-season and post-season All-Star, won the Most Valuable Player over Albie Pearson and Rookie of the Year over Brooks Robinson and Don Demeter,[4] He slumped after that and spent the rest of his career playing for the Atlanta Crackers (1957), Wichita Braves (1957), Dallas Rangers (1958), Monterrey Sultanes (1958), Nuevo Loredo Tecolotes (1958), Charlotte Hornets (1959) and Charleston ChaSox (1959).