A product of Scottish Schools U16 and U18, Sinclair went on to captain both Glasgow and Scotland at U18, U19 and U21 age group levels.
[2] Sinclair also played in the Scottish Inter-District Championship of the 1997-98 season for Glasgow against Edinburgh Rugby.
[3] In 1997, Sinclair captained the Scottish Silver Thistles, an undefeated Scotland Development XV which toured New Zealand.
[4] For the 1998-99 season onwards, Sinclair played for Edinburgh Rugby winning player of the inter-district Tri Series in 1999.
He was a player for the Xodus Steelers, a veteran Scottish Sevens side that contested the Dubai International Veterans Rugby 10's, winning in 2012 and then managing the side in 2013 to back to back victory.