To determine the most overpaid and most underpaid players, Forbes used Pro Football Reference's "Approximate Value", which was adjusted to produce a "per-game number" from the last three seasons. The adjusted figure was then compared to the average per year (APY) of the player's contract, via Spotrac.com.
Any listing of "overpaid" and "underpaid" players in the NFL is going to have flaws. Unlike the other three major sports leagues, NFL contracts are not fully guaranteed (which makes the "APY" a poor measuring stick) and are frequently renegotiated. Also, NFL contracts are based on what a player is going to do, not solely on what the player has already done. Therefore, looking at the previous three seasons (which is about the average span of an NFL career) and ignoring the immediate future is a poor way of determining who is underpaid and who is overpaid.
Topping Forbes' list of "overpaid" players was Minnesota Vikings fullback Jerome Felton, whose $2.5 million per year extension from March didn't jive with his "per game AV". Of course, Felton did go to the Pro Bowl last season after leading the way for Adrian Peterson's 2,000-yard rushing season, so we're pretty sure the Vikings have a good grasp on Felton's value to the offense. Besides, it's not like Felton's "APY" is out of whack with other NFL fullbacks. John Kuhn of the Green Bay Packers, Mike Tolbert of the Carolina Panthers and Michael Robinson of the Seattle Seahawks each have contracts that average $2.5 million per season and Felton's $2.5 million guarantee is slightly higher than the average guarantee those other fullbacks received in their deals.
Vikings tight end John Carlson is No. 2 on Forbes' list. Carlson certainly qualifies as his five-year, $25 million contract was a stunning number when he was signed as a free agent in 2012 after missing the entire 2011 season with a shoulder injury. Carlson was a bust for the Vikings last season, catching just eight passes for 43 yards after banking $8 million in cash in 2012. That lack of production and a reduced role in the offense led to Carlson agreeing to a pay cut in March, dropping his cash compensation from $3 million to $1.55 million for the upcoming season. So while Carlson's APY of $5 million (which is the non-renegotiated figure. His new APY is $3.8875 million) is among the top 12 or so among NFL tight ends, his cash compensation for 2013 is actually tied for 33rd among active tight ends.
Third on the list is Ricky Jean-Francois of the "San Francisco 49ers", who provides an excellent example of how players receive contracts based on what they're expected to do. Jean-Francois, who spent the last four seasons with the 49ers, signed a four-year, $22 million contract with the Indianapolis Colts as a free agent in March. While Jean-Francois was a key backup in San Francisco – who allowed the second-fewest rushing yards over the previous four seasons – he is expected to start for the Colts, who ranked 29th against the run in 2013.
Forbes' underpaid list features recent first-round picks with three years of experience who are nearing the end of their rookie deals. Hakeem Nicks, who is scheduled to be a free agent in 2014, Dez Bryant, Devin McCourty and Maurkice Pouncey are all fine examples of players who can be classified as "underpaid". However, the list also includes players who have been productive in the NFL recently, but are on new contracts with new teams that reflect their advancing age and/or injury history.
According to Forbes, the most underpaid player in the league is Cincinnati Bengals linebacker James Harrison, who refused a pay cut to remain with the Pittsburgh Steelers in March and was signed to a two-year, $4.45 million contract by the Bengals in April. A few years ago, Harrison was one of the most feared pass-rushers in the sport, but his production has dipped (six sacks last season) as he enters his mid-30s. It is not unreasonable to see a player's compensation decrease along with the expectations for his production. Harrison may very well outproduce his contract with the Bengals this season, but a downward trend in productivity resulting in a lower salary is not a surprise.
Harrison is one of five players on the "underpaid" list who are a.) over 30 and b.) were released by their previous team for cash or salary cap reasons. Cornerback Antoine Winfield (36), linebacker Karlos Dansby (31), offensive tackle Max Starks (31) and defensive end/linebacker John Abraham (35) were also cap casualties this offseason, released into a buyer's market that had little to no interest in paying older players at the premium rates they had earned during their prime production seasons. The free agent market was even less inclined to pay running backs with lengthy injury histories, which is why Ahmad Bradshaw, the No. 2 player on Forbes' list, who signed a $2 million contract with the Indianapolis Colts in the middle of June that included just $250,000 in guaranteed money.