He's 20 and is currently behind 4 other strikers. He's good but still unproven at Premier League level in comparison to Aguero, Tevez, Balotelli and Dzeko. Man City may not be happy to sell but Guidetti no matter how good he is, is facing the possibility of being a bench warmer at City for another 2-3 years which he may not want.
Wouldn't they be better off loaning him again? I'm sure there would be a number of good clubs willing to take him on loan after the season he had in the Netherlands.
Seems like they would be silly to sell him so soon, can't see it myself.
Don't forget Adeybayor who is available on a free aparently!