Benitez will loan out some of his young guns before the loan window closes but has told others they are needed as back-up for the first half of the campaign.
He told the Evening Chronicle: “When I was in the Academy of Real Madrid I was desperate to go to the first team training camp. When you are so close and you stay around you will improve even more.
“If you don't get the chance to play in the first team you can still play with the Under-23s.
“You will be training with the first team though. You will always have time afterwards to go out on loan.
“When you get this close it is better to stay around."