While other sites and analyses may look at standard statistics like yards per carry and completion percentages to determine the best player in the league - the MVP - we like to dig a little deeper here at numberFire. We like to use our favorite metric, Net Expected Points (NEP), and its position-specific variations.

Since common numbers such as yards, completions, and touchdowns don't tell the whole story about a player, we can use NEP to see who is truly separating himself from the pack and adding value to his team.

Because this advanced metric alters depending on the position being analyzed, we'll look at each of the skill positions individually through the first 15 weeks of the season to determine the most valuable player at each position. You will see higher NEP values for quarterbacks and receivers than for running backs due to the nature of their production.

Take a look below.

Top-5 NEP Performers by Position Through Week 15

Quarterbacks: 1. Peyton Manning – Denver Broncos
Season Passing NEP: 163.84
Passing NEP per drop back: 0.31
Last week: #2

And just like that, we get another big swing in points from Manning and Aaron Rodgers in one week. A week after seeing Manning struggle against the Bills, Rodgers put up even more of a dud (-12.21 Passing NEP) against the league's best pass defense according to our power rankings.

Manning's stats weren't exactly eye-popping, but he took care of the ball, completing 70% of his passes for 233 yards and a touchdown. That allowed Manning to contribute 13.72 Passing NEP on the day, the fourth-best mark of Week 15.

But while Manning finally turned things around, his successor in Indianapolis struggled yet again. Andrew Luck had another rough week, losing 9.63 Passing NEP for the Colts despite a victory over divisional rival Houston. This is actually the third time in the past four weeks that Luck has underperformed despite a win by the Colts in the end. The recent rough patch has put Luck outside of the top five this week.

Playing Catch Up
2. Aaron Rodgers: 156.32 Passing NEP, 0.32 per pass (last week #1)
3. Ben Roethlisberger: 136.57 Passing NEP, 0.24 per pass (last week #3)
4. Tom Brady: 130.03 Passing NEP, 0.24 per pass (last week #4)
5. Drew Brees: 122.11 Passing NEP, 0.20 per pass (last week #6)

Running Backs: 1. Le’Veon Bell – Pittsburgh Steelers
Season Rushing NEP: 20.91
Season Target NEP 38.72
Rushing NEP per carry: 0.08

Note: These rankings are a reflection of a simple formula that combines our Rushing and Target Net Expected Points metrics. Adding in the Target NEP (how the player does on all targets) allows us to evaluate the overall impact a running back has in the passing game as catching the ball is more effective than running ball.

Even when you lose ground, you can still win. Le'Veon Bell may have scored two touchdowns, but he didn't put forth his most effective week on the season running the ball (-1.14 Rushing NEP) in Week 15. But thanks to Justin Forsett's losing 3.10 Rushing NEP for the Ravens, Bell maintains the top spot.

Bell does appear to have a new challenger, though, in Jamaal Charles. Charles is running the ball more effectively than anyone right now and has 3.84 more Rushing NEP than Bell. And while Charles is still involved in the passing game for the Chiefs, it's a matter of volume for Bell compared to everyone else, as he has twice as many targets than anyone else on this list besides Matt Forte.

With Bell's lead in Target NEP because of his usage in the passing game, it's hard to imagine anyone's topping him with two weeks left. Eddie Lacy is the next best back in Target NEP, but he has been very average on the ground, hurting his overall chances.

Playing Catch Up
2. Jamaal Charles: 24.75 Rushing NEP, 5.55 Target NEP, 0.14 per rush
3. Justin Forsett: 18.83 Rushing NEP, -2.68 Target NEP, 0.13 per rush
4. Marshawn Lynch: 15.40 Rushing NEP, 7.30 Target NEP, 0.07 per rush
5. Matt Forte: 10.21 Rushing NEP, 8.94 Target NEP, 0.04 per rush

Receivers: 1. Antonio Brown – Pittsburgh Steelers
Season Target NEP: 91.65
Reception NEP per target: 0.85
Last week: #1

Note: Receivers and tight ends are evaluated on Target NEP rather than Reception NEP. Target NEP will look at how a player is doing on all targets received, not just on the passes he catches.

Just three weeks ago I mentioned how tight the standings were among this group of receivers with just 14 points separating first and sixth. After injuries forced top players out (Julio Jones and T.Y. Hilton) last week and Jordy Nelson and Randall Cobb suffered from Rodgers' poor game, the gap between just first and second is 12.03 Target NEP and a massive 23.13 points between first and sixth.

If anyone can catch Brown, it will be his former teammate Emmanuel Sanders, the better receiver for the Broncos this year. Sanders has had four top-five weekly finishes in Target NEP with an additional finish in the top-10. While Nelson has just as many top-five finishes as Sanders, Brown is the only one to top them both with six top-five finishes to go along with two other top-10 finishes.

Sanders will have to put up monster games the next two weeks though as Brown could eclipse 100 Target NEP on the season within the next two weeks. Brown needs to tally 8.35 Target NEP in his next two games to become only the fifth player since 2000 to top 100 Target NEP. Brown has a legitimate shot at equaling -- or even surpassing -- Wes Welker's top Target NEP of 104.76 set in 2011.

Playing Catch Up
2. Emmanuel Sanders: 79.62 Target NEP, 0.89 Reception NEP per target (last week: #2)
3. Julio Jones: 74.33 Target NEP, 0.87 Reception NEP per target (last week: #3)
4. Randall Cobb: 71.46 Target NEP, 0.93 Reception NEP per target (last week: #5)
5. Jordy Nelson: 71.00 Target NEP, 0.89 Reception NEP per target (last week: #4)

Tight Ends: Rob Gronkowski – New England Patriots
Season Target NEP: 67.89
Reception NEP per target: 0.91
Last week: #1

The race for second place among tight ends is in full swing. If you thought the gap between first and second for the receiver position was big, it's even worse with the tight ends with 19.39 points separating first from second. While the 2011 version of Gronk set the record in Target NEP for a tight end (102.9), this year's version only needs 5.46 points to end up as the third best since 2000.

The guy that Gronkowski would have to pass is none other than Antonio Gates, our third best tight end this year. Gates was very average in Week 14 and sits just a half-point behind Travis Kelce for second. A big day by Greg Olsen however, will make second place a three-horse race.

Olsen caught 10 of his 13 targets for 110 yards, as the Panthers squeaked by the Buccaneers. Olsen has been a big safety valve for the Panthers and their limited receiving corp and has the team clinging to playoff hopes. If Olsen can put up 9.93 Target NEP again in each of the next two weeks, they just may get a chance to host a playoff game.

Playing Catch Up
2. Travis Kelce: 48.50 Target NEP, 0.82 Reception NEP per target (last week: #2)
3. Antonio Gates: 48.03 Target NEP, 0.90 Reception NEP per target (last week: #3)
4. Greg Olsen: 46.34 Target NEP, 0.71 Reception NEP per target (last week: #4)
5. Jason Witten: 31.82 Target NEP, 0.77 Reception NEP per target (last week: #7)