Sinclair spoke out after grabbing a superb last minute try which enabled Hawks to wreck Heriot's Premier title hopes at Old Anniesland. Heriot's looked home and dry at 13-12 ahead - until Sinclair sent a teasing chip into the danger-zone, hacked it into the touchdown area and won the race by a fingertip.
The scrum-half has played only five minutes of a pre-season friendly for the Warriors since clinching a contract at the relatively advanced age of 27.
Sinclair impressed when he turned out for Glasgow in a handful of games at the end of last season. He said: "It has obviously been a frustrating few months for me. The bosses at Glasgow have told me they are not playing me because they haven't seen enough of me in action.
"Hopefully they will now change their attitude and at least give me a shot."