The former Liverpool player has not fulfilled expectations at the Reebok Stadium since a £4million move in the summer of 2011.
And Frenchman Ngog has now indicated he would be interested in quitting England to return to his homeland, where Bordeaux are said to have been tracking him since January.
He said: "I have a contract until 2014 with Bolton. If there is an opportunity for them to cash in on me and for me to play at the top level again, it will be fantastic.
"To return in France in Ligue 1 could be fantastic for me and my career. I have enjoyed my time in England so far and I can deliver at the top level."