He played in Major League Baseball (MLB) for the Washington Senators and Chicago White Sox.

[1][2][3][4][5][6][7][8] Atz played in the major leagues during 4 seasons, 1902 for the Washington Senators and 1907-09 for the Chicago White Sox.

In four major league seasons, Atz played in 209 games, had 605 at bats, 64 runs, 132 hits, 21 doubles, three triples, 49 RBIs, 23 stolen bases, 69 walks, a .218 batting average, .304 on-base percentage, .263 slugging percentage, and 33 sacrifice hits.

His first managerial assignment was for the Providence Grays of the East League in 1911, and he failed dismally, losing 69 of 108 games (.361).

During their seven-year skein as kings of the Texas League, the Panthers won over 100 games five times – with records of 108–40 (.730) in 1920, 107–51 (.677) in 1921, 109–43 (.717) in 1922, 109–41 (.727) in 1924, and 103–48 (.682) in 1925.