There us a difference between a players quality level and his quality of play.
The first, to me is his league level ie 59 quality at level 8 or 5 star.
The more important quality is his ability to play and contribute or his overall rating. These are the players I rate over and above the league quality.

It is easy to see which players contribute, in your team and the opposition, if your look. The ones that contribute in the opp team are the ones you want to defend against, and the ones that don't, are the weaker ones.