As valuable as size, speed and strength are, they do have limitations when evaluating players. Pro football history is full of imposing physical specimens who didn't pan out because they had some weaknesses that more than offset their elite physical attributes (e.g. Brian Bosworth, Mike Mamula, Lawrence Phillips).
Despite the clear historical warnings, in just about every draft there are teams that will select a player based on his physical attributes, ignoring his glaring football deficiencies.
The 2010 Denver Broncos offered a good example of this when they drafted last year's somewhat flawed quarterbacking phenom, Tim Tebow. The recent comments of John Elway, one of the Broncos' new head honchos and a man who knows a thing or two about quarterbacking, that Tebow is still "very raw," even after a year in the system, say their organization is probably going through a serious case of buyer's remorse.
This is something that teams should keep in mind when considering drafting former Auburn Tigers quarterback Cam Newton in the first round of the 2011 NFL draft. His physical characteristics are off the charts (6-foot-5, 248 pounds, 4.59 40-yard dash time), but a tape review of his 2010 season shows several significant weaknesses that make him more than a bit of a first-round risk.
There are a wide variety of areas that should concern NFL teams and were apparent when I went back and reviewed tape on Newton, but the three most significant are: