For the uninitiated, net yards per attempt is a derivative of the grandfather of all passing stats: yards per attempt (YPA). In actuality, YPA may be the single most telling stat in football.
Like its stately cousin, NY/A helps us understand what happens each time the quarterback drops back for a pass. For reference, NY/A is calculated by subtracting sack yardage from passing yardage, then dividing by passes attempted plus sacks. In other words:
(yards passing - sack yards) / (pass attempts + sacks) = Net Yards per Attempt
There's no point in rehashing all the reasons why Blaine Gabbert is unlikely to ever become a viable NFL starter; it's all been covered before.
For the time being, let's narrow the focus down on just how bad Gabbert has been historically.
In 2012, his NY/A was 5.01 and his YPA was 6.0. As mentioned, both numbers represented low marks in the NFL.
The good news is that despite finishing last in the league, Gabbert's 2012 was still a significant improvement over his 2011.
It's easy to see, that he did experience a real, measurable improvement over his historically bad play in 2011. The problem is that his play still rates as historically bad.
Gabbert went from the 25th worst season in NFL history to merely the 121st worst season in terms of YPA.
His NY/A numbers were even worse. Using NY/A+ (which is indexed to league average), Gabbert had the third worst NY/A season in history in 2011. In 2012, he put up merely the 37th worst indexed season.
Obviously, the Jaguars' line is terrible, and that is helping to contribute to Gabbert's poor performance. NY/A has a sack component, and while Gabbert's pocket awareness is well below average, there are plenty of times he simply has no chance to even try to make a play.
Beyond that, however, Gabbert is bad when he does manage to get the pass off. He checks down too quickly and isn't as accurate as he needs to be.
Anything is possible in the NFL, but right now, Gabbert has the 10th worst YPA in NFL history for passers with at least 600 attempts. He's ranked between the likes of Ryan Leaf (ninth) and Shane Matthews (12th). It's highly unlikely he ever becomes a quality player.
When it comes to getting the ball downfield, he's not just bad. He's historically bad.