He joined the football academy at St Johnstone when he was 12 years-old.
[5] Sinclair made his Scottish Premiership debut for St Johnstone in May 2023 against Ross County.
He received praise from on-loan goalkeeper Remi Matthews for his performances.
[6] Sinclair started two matches for St Johnstone in the Scottish League Cup at the start of the 2023–24 season, but suffered a double break of his arm and an elbow dislocation in a behind closed doors friendly in August 2023, which had to be operated on.
[9] Former St Johnstone goalkeeper Alan Mannus for his ability to play out from the back with his feet.