When Sinisalo started his ice hockey career in the 1970s, NHL teams did not scout extensively in Finland. The first Finnish ice hockey player in NHL was Matti Hagman for the 1976–77 Boston Bruins. However, NHL scouts were so impressed by Sinisalo's talents that they made an exception by signing him as a free agent after his 1980–81 season with HIFK, where he scored 27 goals in 36 games.
Initially, Sinisalo began his ice hockey career in the 1970s when NHL teams did not thoroughly investigate Finnish talent. The first Finnish player to join the NHL was Matti Hagman for the Boston Bruins during the 1976–77 season. Nevertheless, NHL scouts were so impressed by Sinisalo's skills that they made an exception and signed him as a free agent following his 1980–81 season with HIFK, where he achieved 27 goals in 36 games.