Capped by Scotland at youth and schoolboy level, Sinclair joined Nottingham Forest as an apprentice from Stirling Boys Club, and he signed professional forms in October 1982.
It was in a loan spell with Fourth Division side Wrexham in the closing stages of the 1983–84 season that Sinclair gained his first Football League action.
By the early stages of the 1991–92 campaign, he was out on loan again though, spending time with Walsall before beginning a five-year stay with Stoke City in a £25,000 move in November 1991.
He was not selected again after a 5–0 thrashing at Exeter City on 4 April 1998 and manager Kevin Ratcliffe announced later in the month that Sinclair's contract would not be renewed.
[6] Sinclair never played professionally again after leaving Chester and has spent most of his time working as goalkeeping coach with Stoke City, where he initially was registered again as a player.