For those of you who follow me on Twitter, it will come as little surprise to you that I am a vehement, unapologetic mega-nerd. I’m a Star Wars fan, a Dungeons & Dragons player, and a total comic book fiend. 

Still, my biggest nerdy passion is the trading card game, Magic: the Gathering, where you take on the role of a planeswalker -- essentially a powerful wizard with a command of various different kinds of magic -- and duel with other sorcerers of your ilk. It’s the same thing as being obsessed with Harry Potter, except here you actually get to sling the spells instead of just reading about them.

Avada Kedavra, meet Force of Will.

The tough thing about Magic, though, is that when building a 60-card deck to play with, you have a lot to consider: what's my main strategy? What are the strongest cards that make that game plan go?

NFL teams have a similar process to go through when they make free agent signings: they have to parse through the available players and determine which ones have the best value for their team, which players they can fit into their 53-player “deck” that will best help to serve their team agendas. A lot can go wrong in roster building, so teams have to use those spots wisely.

This got me wondering: which NFL free agent signings in recent years have provided the most value?

Channel, Fireball

No matter how we measure it, value all comes back to whether or not a player contributed to his team’s betterment while with that team. We can look at numberFire’s Net Expected Points (NEP) analytic to help us measure that.

NEP is an analytic helps us take the numbers we get from the box score and shows how that player did versus expectation. By adding down-and-distance value to standard box score information, we can see just how much each play and each team as a whole influence the outcome of games. If a player gains five yards on 3rd-and-2, it means more to the game than it does on 3rd-and-10, and those plays should be valued accordingly. For more info on NEP, check out our Black Lotus, and which were the Sorrow’s Path of the market?

Time Walk: Opportunities

The first thing I want to examine is who got the most playing time out of their signed players. One way that we can look at value is the value of actually having your lineup filled on game day.

The table below shows the top 10 players who accrued the most total opportunities (attempts or targets) over the course of their contracts.

It should come as no surprise that seven of the top-10 (and all of the top-five) players in this metric are quarterbacks. The signal-caller touches the ball almost every play, so it shouldn’t be surprising that these are the premier opportunity hogs in terms of free agent contracts. It is interesting to see high-volume Washington wide receiver Pierre Garcon up there with the passers, as well as premium Tampa Bay Buccaneers deep threat Vincent Jackson. BenJarvus Green-Ellis is perhaps the most shocking player in the top-10, but he toted the load for the New England Patriots when he was on the team, racking up chances.

If we ruled out quarterbacks from this list, the next three players would have been running back Darren Sproles (492 opportunities with the New Orleans Saints since 2011), Ahmad Bradshaw (467 with the New York Giants since 2011), and Rashad Jennings (443 with the Giants since 2014).

If we were to look at average annual opportunities by contract, the top 13 players would be quarterbacks. Frank Gore, however, earned himself 318 opportunities so far into his 2015 contract with the Indianapolis Colts and sits 14th, just ahead of Cedric Benson's 2011 contract with the Cincinnati Bengals.

Bounty of the Hunt: Total NEP

Next, we must take a look at pure, unadulterated value. This is how truly valuable each player was for his team. The table below shows our first measure of this: which 10 free agents have generated the most Total NEP in free agent contracts signed since 2011?

It’s pretty compelling to note that four of the top five free agent successes from the past half-decade were either connected to Peyton Manning, or are Peyton Manning himself. Garcon and Reggie Wayne were cornerstones of Manning’s Colts wideout corps, and capitalized on new deals in 2012 – same as Manning himself. Emmanuel Sanders, of course, saw career years when he joined Manning’s Broncos for the past two seasons.

The only non-Manning-related free agent in the top five is Jackson, who didn’t miss a beat when he left the San Diego Chargers. In his four seasons since signing that contract, he’s already racked up 512 targets for the Bucs, remaining one of the most valuable deep threats in the league.

We also see one running back and one tight end in this group, Sproles on his Saints contract, and Delanie Walker with the Tennessee Titans. Fascinatingly, both are highly undervalued in the public eye, but both have produced very well. The next four free agent running backs with the most Total NEP produced in their contracts are Danny Woodhead (45.54 with San Diego since 2013), DeAngelo Williams twice (35.06 from 2011 onward with the Carolina Panthers, and 34.44 last year with the Pittsburgh Steelers), and Bradshaw (32.82 with the Giants).

If we examine annual average Total NEP, many of the usual suspects appear on the board, but they are joined by James Jones’s 2015 one-year contract with the Green Packers, which generated 93.22 Total NEP, as well as Josh McCown's one-year contract with the Chicago Bears in 2013, which saw him earn 89.21 Total NEP. Rounding out the top 10 are two 2015 contracts: Michael Crabtree with the Oakland Raiders (86.50 Total NEP) and Jeremy Maclin with the Kansas City Chiefs (86.14).

Farseek

It’s tough to project which players are going to come out of free agency and help one’s team in the future. There are things to consider like fit and chemistry in addition to the obvious money concerns. It’s imperative that NFL scouting departments not only have an ability to scout prospects, but also can sift through the veteran minefield on the market. These players have rewarded those efforts immensely, and some still have a ways to go on those deals. They could prove even better investments.