The former Arsenal winger is trialling at Selhurst Park.
His agent Leon Callander told the South London Press: "The more Quincy plays for Ian Holloway the more he is going to do.
"He's not even at his optimum. Judging from what I saw at Panathinaikos, in another two games he will start to set it alight.
"There is a lot of interest from Turkey and other clubs in Greece but he wants to be here. He feels he has got a point to prove."