Because there were some rumors about loaning him out. Anyway Munir, Adama and Halilovic can't stay in B-team next year - it's in their contracts. So they will either go to A team or they will be sent on loan. Sandro has no such clause, so he can stay in B-team and help A-team when necessary.
Munir situation will depend on Deulofeu - I don't think we'll keep both of them in A team. Also I believe team leadership wants him to have enough minutes, not sit on bench - and that's unlikely behind Trident. If they want him to develop his talent loan is necessity.
So ironically Sandro might have bigger chance to play for A-Team next year, precisely because he's rated not so highly as Munir.
There are also rumors of Samper being sold to Liverpool. Don't listen to what the papers say about our young players. Deulofeu will not be returning next season if Lucho remains coach. He doesn't like wingers (Poor Pedro) and Deulofeu has an apparently cancerous attitude (I don't personally believe this, btw). And there are plenty of opportunities to give Munir minutes if he's part of the first team. Even giving him the minutes Pedro is getting this season would be hugely beneficial, but that would require Pedro to leave first.