No, I did not do any training to him, he's a generated player for my team 2 weeks ago.
Edited: Oh ya, I just noticed that he can be in U21, I was too concentrated in playoff for now so did not notice that he is 18 and starter potential, anyway I'm not planning to train him until playoff because I'm improving my whole team stamina for playoff.
Is your stamina so bad???
I am a fan of stamina, I have many players 6+, but I keep several 4 and I am pretty satisfied of them. May be your players have an average of 1.2 (so yes, you need at least one pop), but I would concentrate on primary skill now to increase PO performance.