For me Chalobah has to be the most likely to make it here atm. Of course a lot depends on his attitude, but to be key player in a good championship side at the mere age of 18 is something, especially that the position he plays in usually requires a lot of experience. Piazon comes second. He has excellent technical abilities and the club seem to have great faith in him and are willing to give him a full chance. I was very impressed by his movement during the preseason tour. I still believe his best position is as a second striker and not on the wing. Feruz comes in third. He seems to built for the EPL. He has speed, strength and stamina. His movement is good but needs to work on his finish, imo. I think a loan would tell us more about Islam, but he is definitely a great talent. Lots of other excellent talents, but with a team like Chelsea, betting on youngsters is always a long shot. The most obvious two would be Josh and Ake. There are also some great younger prospects like Charly Musonda and Ruben Loftus-Cheek but they still have a long road in front of them.