Beginning in 1979, Mayer alternated between indoor and outdoor soccer for several years. While on contract with the Sockers for the outdoor season, he joined the Pittsburgh Spirit of the original Major Indoor Soccer League (MISL) for the 1979-1980 MISL season. He was selected as second team All MISL with the Spirit. In 1980, the Sockers traded Mayer to the California Surf. He played two seasons with the Surf. Between the 1980 and 1981 outdoor seasons, Mayer also played with the New Jersey Rockets of the MISL. When the Surf folded after the 1981 season, Mayer concentrated on playing indoor soccer for the remainder of his career.