What is usually misunderstood is that these guys like Kiper and Mcshay are using info from former scouts and former GMs and rarely using info on the people that are there now. Also they don’t take into account of each organization’s strategy. They usually plug a perceived need based on how they rate players.And this is why I don't believe an NFL team is going to use a top 15 to 20 pick on him. It's too important of a position to assume he's going to get back to elite ability.
Point is anyone putting Tua as a Top 15 pick is doing so based purely on his qb ranking and not because inside sources are indicating that someone is seriously looking at him in the top 15. I just find it hard to believe that he is a sure fire top 15 without going to combine.