After graduating in 1974, he was drafted first by the
Baltimore Comets of the
North American Soccer League (NASL). In the 1974 off-season, while playing in England for
Southend United, then in the
Football League Third Division, Mayer earned the distinction of scoring a goal from the goalkeeper position. In 1976, the Comets moved to San Diego and renamed their franchise, the
Jaws. The team moved again in 1977 after only one season in San Diego, this time to Las Vegas, becoming the
Quicksilvers. That year, Mayer earned NASL Second Team All Star honors. In 1978, the team moved again, back to San Diego where they took the name
Sockers. Mayer remained with the team through all these moves and was named the 1978 NASL American Player of the Year. 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. He returned to the Rockets for the 1981–1982 season before moving back to the San Diego Sockers which, while still officially part of the NASL, was playing in the MISL during the indoor season. While the Sockers had been a poor outdoor team, they quickly became the dominant U.S. indoor franchise, winning the MISL 1982-1983 championship. Mayer was named the MISL MVP and was the MISL All Star team goalkeeper that year as well. Mayer had a short tenure as player/head coach of the MISL's
Las Vegas Americans in 1984–85, but was relieved of his coaching duties just ten games into the season (after going 4–6) and was replaced by Don Popovic. Mayer remained with the Americans strictly as a goalie and went 17-12 while splitting time with Keith Van Eron. After the Americans' franchise folded the following summer, Mayer signed with the
Kansas City Comets for the 1985–86 season and became an MISL All-Star for the second time. Nicknamed "Kamikaze" for his reckless all-out style of play, he became a fan favorite throughout his time in Kansas City, spending his final four seasons as a Comet before retiring at the end of the 1988–89 season. Mayer played his last game on April 12, 1989, against the Wichita Wings, and he finished with a regular-season won-lost record of 56–56 in Kansas City. In 2013, the Comets retired his jersey and it is now displayed hanging in the Silverstein Eye Centers Arena. == National team ==