It's a nonbrainer?
He should play games, and in Barcelona A he seems to be above Puig and Pjanic in Koemans order, but he is behind Frenkie, Pedri, Sergi, Sergi and Gavi. Being sixth in line makes it tough to get very much playing time when everybody's fit, and it's easy to be called in when needed?
What are the limits for when you must register for A/cannot play for B?
I'd like to say 10 without researching, but I am not 100%. It is around that number though.
I think we could of done the same with Gavi, but it seems Koeman believes in him completely, and I can only assume that he is looking incredible in training. If he has a level of trust close to Pedri, then it makes sense to give him a first team number though.