We have one of the best defensive records in the Prem, yet our clean sheets were few and far between.
From Duff's angle, yeah, play him, why not? I guess from the clubs angle, it's why remove Distin or Jags from the starting line up if it's working out ok? Is he 'better' than those defenders to a point that he should start ahead of them?
As fans, we can't answer that, but as a trainer / coach, who's job it is to watch each player very closely, they can. He might get a starting spot with other teams, but that's not very relevant as to whether he is going to get a starting spot here.
He's only 21, so it's not like he is at a career crossroads. Eventually his chance will come, but I don't think us signing Alcaraz will affect that. We need numbers.