The winger moved to the Etihad Stadium from Swansea City two years ago, but has started only two Premier League matches for the club.
Sinclair joined West Brom on loan last season, but that switch also failed to work out as he made only eight top-flight appearances for the Midlands club - with only four of those being starts.
Former England Under-21 international Sinclair has expressed his frustration at the manner in which his career has stalled and the 25-year-old is eager to play first-team football.
"It has been very frustrating for the last couple of years," he told Sky Sports.
"I have tried to do as well as I can in training and hope to get a chance but at this moment in time it is hard for me to get a game.
"There are some world-class players here so I can't do much more than keep working hard in training.
"I don't feel I've had the best of chances; I just want to get out there and show why City bought me but I've not had that opportunity.
"I made the decision [to join City] and I have to deal with it, I can't look back and say it was a mistake but the only thing I do miss is playing football.
"I made the decision to come to City and fight it out with all the big players and it hasn't really worked out thus far.
"All I can do is re-evaluate in January and go from there."
