Madge has been watching the entire team in depth the entire pre-season. They wouldn't be there unless there was a reason. He is seeing the big picture of the team, not just the individual players.
They might not offer much individually, and what they bring might not be easily observed - but might be really important to our defensive system - particularly on the edge, where we were very vulnerable last year.
I'd take a hard-working, boring, average player who allows our edge defence to be impenetrable over a flashy superstar who is going to cost us points.