Thomas Smith Sinclair (1880 – 1968) was a Scottish footballer who played as a goalkeeper at the start of the 20th century.
At the start of the 1906–07 season, the Celtic goalkeeper Davey Adams cut his hand during a benefit match at Ibrox[5] – the injury was caused by a nail which had been inserted through a goal-post for a five-a-side tournament – and as a gesture of goodwill, Rangers loaned Sinclair (who had lost his starting place to Alex Newbigging) to Celtic whilst Adams recovered from injury, and this is the first known transfer between the two Old Firm clubs.
Sinclair played six league fixtures and three Glasgow Cup ties for Celtic, keeping clean sheets in every match bar his final game, where Celtic won 3–2 in the Glasgow Cup final.
[9] During Sinclair's spell at Newcastle the club won the English First Division twice and the FA Cup once (as well as reaching two further finals), but he was unable to displace fellow Glaswegian Jimmy Lawrence (the Magpies' all-time record appearance record holder) for long enough to claim any medals.
He later returned to Scotland and played for clubs including Dunfermline Athletic and Kilmarnock, but again was never the first choice in his position.