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 the 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.