[4] Haddock was born in Newcastle upon Tyne,[4] and joined his home-town club as an apprentice in 1978, turning professional the following year.
He played in a calm and collected manner and got a good run in the side during 1981–82 but lost his place halfway through the following season following the arrival of Glenn Roeder and Jeff Clarke.
He remained at the club, playing only infrequently, and had a spell on loan at Burnley, before leaving for Leeds United in July 1986[5] for a fee of £45,000.
[7] Under the stewardship of Howard Wilkinson "Fish", as he was known, became a crucial part of the defensive unit alongside Chris Fairclough that won promotion as Second Division champions in 1989–90.
His career was cut short however when he suffered a freak injury in the second leg of the League Cup semi-final against Manchester United in 1991, as Leeds went out 3–1 on aggregate.