He played on loan for Cape Town in 1975-76 during the NASL’s off-season before returning to the U.S. in 1976. That spring Hartze joined the Tacoma Tides of the American Soccer League on loan from the Rowdies. He was then traded to the Sacramento Spirits in June 1976. In late July after the firing of head coach Dick Ott, he was named player-coach with eight games remaining in the season, guiding the Spirits to a 3–1–4 record.
