Before breaking out, Atlanta Falcons running back Devonta Freeman entered the 2015 season with some of the worst efficiency scores a running back can have.

His 2014 rookie season was a disaster, as he was stuck behind a mediocre offensive line and provided with little opportunity to succeed. While he had shown flashes as a receiver, it looked unlikely that he would be able to make an impact behind the more hyped Tevin Coleman, who was handpicked by the new coaching staff to be their featured back. Freeman finished the season as the top scoring back in fantasy football.

Similarly, Blake Bortles was historically bad in 2014, demonstrating a carelessness with the ball and inefficiency that had most ignoring his potential fantasy upside. And while he was every bit as inconsistent as advertised in a football sense in 2015 (18 interceptions and 14 fumbles, with 5 lost), his unexpected 37 total touchdowns and 4,700 total yards propelled him third-place fantasy scoring season.

In 2014, Kenny Stills had just been traded to the Miami Dolphins after posting immensely efficient metrics while a role player for the New Orleans Saints, but he was largely unused and under appreciated in a disaster 2015 season for the Dolphins.

There are countless examples over the years of players who don't play to their their data-driven expectations like these three.

Situations change, players improve and regress, and there's a bit of luck built in as well, meaning that metrics don't carry over from year to year.

Dez Bryant and Aaron Rodgers were two of the most ineffective players at their positions based on our Net Expected Points (NEP) metric in 2015, but no one would argue that their seasons were anything more than an anomaly based primarily on injuries. Based on where they were being drafted, the fantasy football community is clearly willing to overlook their ineffective 2015 campaigns to draft them near the top of the position groups.

But not all players coming off an inefficient season are given that type of slack. And conversely, some players with high efficiency scores are being projected as big-time sleepers. Diving into individual player profiles can give us a more realistic view of which players are worth gambling on and which players we should pass on.

So who are players whose metrics -- whether favorable or negative -- should be ignored based on the opportunity surrounding them?