Jack Zeller

John A. "Jack" Zeller (1884 or 1885 – February 18, 1969) was an American baseball executive. He served as General Manager (GM) of the Detroit Tigers of Major League Baseball from 1938 through 1945.

Zeller served as manager and part-owner of the Springfield Ponies of the Class-B Connecticut League. As the league had three teams from Massachusetts, he led the charge to have the league renamed. He later owned the Pittsfield Electrics of the same league, then known as the Eastern Association. He attempted to develop a new league in Massachusetts in 1916.

Zeller joined the Detroit Tigers of the American League in 1925 as a scout. Zeller served as a scout and supervisor in the Tigers organization from 1938 through 1941. He was appointed GM of the Tigers in 1938, succeeding Mickey Cochrane. He is credited with developing the Tigers' minor league baseball organization. Following an investigation, the Tigers were found to be in violation of the minor league working agreement in 1940, resulting in 91 players being declared free agents by Commissioner of Baseball Kenesaw Mountain Landis. Zeller took full responsibility. Zeller then began to sell off the Tigers' farm teams. He began to believe that the farm system needed to be completely overhauled. In 1944, he proposed a new draft that would end the minor league system, replacing it with "baseball schools".

Zeller stepped down as Tigers' GM in 1945. He was succeeded by George Trautman. Upon leaving the Tigers, he moved to Fort Worth, Texas, where he served as a scout for the East Texas League and Evangeline Baseball League. In 1947, he joined the Boston Braves as their chief scout.

Zeller died of a heart condition in 1969 at the age of 85.