I would actually keep Quincy James (26932672) and make him a guinea pig. He can get left over training.
3rd guy if you 1pos train, or 5th/6th guy if you 2pos train.
He's got good potential, he's 18. You get a slight bonus in merchandize for home grown players.
In the beginning of the season he could fetch 100k, but now you might get 30k. If you keep him and train him you'll get much more.
You'll have to outbid everyone to keep him, and you'll lose 3% I believe.