Rab, you mean defender, right?
Alen, i dont think that he means that Balza is a good def, but rather that Moli isnt any better than him... His man marking, tackle, tactical awareness isnt so much better to prove otherwise... Any kind of core skills a defender should have are also absent!
If Balza, DC, or any other "winger" out there had the same opportunities Moli had to become a better defender, he would have been at least as good as him, (at defending too, mostly because of teamwork, thats the only reason Moli stands out there).
And Moli has only increased his performances lately, not because of his defensive skills, but his nearly helpful contributions forward...