 Stanley started his career with Chelsea, where he turned professional in 1971 and made his league debut at the age of 21, on 16 August 1975 in a 2–1 defeat away to Sunderland in the Second Division.He helped the club to promotion to the First Division in the 1976–77 season, and remained with Chelsea until their relegation in 1979, when, after a summer in the NASL with Fort Lauderdale Strikers, he joined Everton for a fee of £300,000.He failed to show his Chelsea form with Everton, and moved on to Swansea City two years later for £150,000.