If Pozo mk I is anything to go by he'll struggle physically with the step up.
Iker has always struggled physically. He came into the EDS with Foden, Diaz and Sancho, but needed time to bulk up and hold his own, which is why he's still in the academy now at 19 and not in a first team somewhere.
However, having taken that time to bulk up and develop a bit more, he'll probably be better suited than most kids coming through at 17/18.