The beneficiary of a huge salary at Manchester City following his £8 million move to one of the world’s richest clubs in 2012, his three years there proved frustratingly unproductive.
But rather than settle for being paid a great deal for doing very little, Sinclair sought regular first-team football elsewhere.
His move to Aston Villa also turned sour, culminating in relegation last season, but once more Sinclair was not prepared simply to sit tight on a highly remunerated contract.
The 27-year-old will not have to radically alter his lifestyle choices after joining Celtic, of course, but he will nonetheless have taken a wage cut to join the Scottish champions.
It only takes a few minutes in Sinclair’s company to appreciate he can see beyond the material rewards his sport provides. His desire to maximise his achievements on the pitch is inspired by the experiences of his older brother Martin.
A sense of perspective is something Sinclair will never lack, thanks to his sibling’s remarkable story which includes representing Great Britain in paralympic football.
“He has cerebral palsy and he’s had a tough time,” said Sinclair. “He broke his hip and got misdiagnosed when he was 15.
“So my mum was stretching him every day without realising his hip was broken. That was painful for him and he was in a wheelchair for two or three years. We had to move his bed downstairs.
“He has helped me through any difficult parts of my career because he has really been through such a tough time. It makes me realise how lucky I am and it keeps me grounded as both a player and as a human being.
“He is 30 now and has gone on to play in the Paralympics, which was a massive achievement after he was told he wasn’t going to walk again. I couldn’t ask for a better brother. He played at the 2012 Paralympics in London and I played for Team GB at the Olympic football tournament the same year, which was brilliant for both of us.
“He’s got a massive personality and he wears his heart on his sleeve. He is one of the best guys you’ll ever meet.
“He is always bantering and making jokes. He never stops smiling. He’s always winding me up, telling me he’s got more caps than I have. Hopefully, that will change in time! But it’s great to have a big brother who has been through such a lot to keep me grounded.
“Whenever I’m down, whether it’s because of not playing or whatever, he just rings me up and says ‘What’s wrong with you?’ and ‘Why are you moaning?’ ”
Everything in Sinclair’s garden is certainly rosy right now after scoring the winner on his Celtic debut against Hearts on Sunday. He is enthused by the prospect of revitalising his career under manager Brendan Rodgers.
“I went to Manchester City and people mentioned contracts and money,” he reflected. “I’ve been there and done that but Istill have the hunger and passion to play.
“When I spoke to Brendan I told him I wanted the excitement of being back playing games and making sure the best was brought out in me.
“It was a tough time at Villa last season and disappointing for the club. Being relegated means it’s difficult to pick out any positives. My decision to come here is to find the enjoyment and play for a massive club.
“I couldn’t do it under a better manager than Brendan. With him giving me the licence to express myself it means that he will bring out the best in me.
“I was 16 when I first met him, when I went to Chelsea from Bristol Rovers. So I’ve know him a long time. Right from the start, he made a big impression on me.
“He did well with the Chelsea youth team, moved on to take charge of the reserves and hasn’t really looked back since.”
Sinclair arrives in Glasgow as half of a celebrity couple with his partner Helen Flanagan, the glamour model and former Coronation Street actress. He revealed she is already eyeing up potential career opportunities in Scotland.
“She did mention there is a soap called River City up here – maybe she could go on that!,” laughed Sinclair.
“She is just enjoying being a mum right now. We’ve got a little girl (Matilda) who is just one year old. As soon as I find a house, they will move up here. I’ve got used to the fame side of things. We are just normal people, we do normal things, like going to Nandos”
That is one footballing stereotype Sinclair happily fulfils.