In the history of sports there is always that guy that jumps almost out of nowhere onto the scene and is talked about constantly in the media as being a sure fire prospect.  Even though he may have had no prior success at the previous level. One of the reasons for this might be the increasing trend towards looking at mostly size and other intangibles, such as arm talent or speed.  

One precipitating factor is the combines.  Players can begin competing in these as early as eighth grade.  They are based on things such as speed, size, agility, arm strength, and quickness.  These are all things that are necessary to succeed in the game, but are often over stressed compared to play on the field.

For example, Jeff George was considered to be an average college quarterback never passing the 3000 yard mark.  Even at the time, this was considered to be good, but not great. After finishing his college career, he participated in an NFL combine where he blew away the scouts with his prototype size.  He then went on to play out a long, but very average career for multiple NFL teams, mostly as a journeyman.

Some of your best players are often low draft picks who are overlooked because of their underwhelming combine statistics.  Examples of this are Tom Brady, Russell Wilson, Mike Singletary, and the list could continue on and on.

As the draft process continues to grow, the picks will most likely come from intangibles rather than on the field play.  This will make the continued busts in the NFL even more frequent.

There is no real way to no for sure the best players possible becasue there is no way to look inside a players chest. Although one way to start is to actually start paying attention to hwo they play on the field.