The 2017 class of free agent running backs will feature some enticing players. There's Latavius Murray, the 27-year old back with the Oakland Raiders who went to the Pro Bowl in 2015; Mike Gillislee, who averaged an NFL-best 5.7 yards per carry with the Buffalo Bills this past season; LeGarrette Blount, coming off of his second Super Bowl championship with the New England Patriots, and the leader in rushing touchdowns in 2016; and, of course, Le'Veon Bell, the Pittsburgh Steelers' star offensive weapon who built a solid case for league MVP even though he only played in 12 games.

But one word of advice if you're a GM thinking of signing any of these players to a free agent contract: Don't.

Just look back at the running backs who were signed to large free agent contracts or extensions within the last five years. Even the best running back of this generation, Adrian Peterson, was not a great investment. AP signed a seven-year deal worth up to $100 million in 2011, hen won MVP honors in 2012 when he rushed for over 2,000 yards, and was also a Pro Bowl running back in 2013 and 2015, but he missed four games in 2011, 15 games in 2014 due to suspension and 13 games in 2016. It's a foregone conclusion that Peterson will be released this year, but most important of all, the Minnesota Vikings never won a playoff game during the first six seasons of that deal.

Here are some other cases, in case you're not convinced.

2012

• Baltimore Ravens signed Ray Rice to a five-year, $35 million deal (up to $40 million with incentives). Rice did help the Ravens to a Super Bowl win in 2012, but was already playing like a worn down back by 2013, averaging just 3.1 yards per carry. His serious off-field issues aside, Rice was a lesser player in the first season of his deal, and downright bad by year two.

• Houston Texans signed Arian Foster to a five-year, $43.5 million deal. Foster led the NFL in touchdowns in 2012 and was in the Pro Bowl in 2014, but missed half the season in 2013 and 12 more games in 2015. The total output for his five-year deal was 3,375 rushing yards, which would be 844 rushing yards per season over five years. In his final season with the Texans, Foster averaged only 2.6 yards per carry.

• Chicago Bears signed Michael Bush to four-year, $14 million deal. The Bears paired Bush with Matt Forte and he ended up playing just two more years before retiring, averaging 3.4 YPC in Chicago. This was just a complete waste of money.

• Carolina Panthers signed Jonathan Stewart to a five-year, $36.5 million contract extension. He's averaged 628 rushing yards per year ever since and 4.0 yards per carry. A perfectly decent, albeit oft-injured and unspectacular running back being paid like an elite player. 

Now here's an exception to these three huge mistakes, and possibly the reason that NFL teams continue to make said mistakes: The Bears signed Matt Forte to four-year, $32 million deal and he averaged 1,625 total yards and nine touchdowns per season. It's a reasonable value even though Chicago never made playoffs in any of those years.

Next, the Seattle Seahawks signed Marshawn Lynch to four-year, $32 million deal, which is an incredible value, and the team won the Super Bowl in 2013, nearly repeating in 2014. Lynch was the best signing of the last five years perhaps, but his return on investment is almost certain to not be matched without a lot of luck. And still, Lynch's extension in 2015 turned out to be of horrible value for the Seahawks.

2013

• Atlanta Falcons signed Steven Jackson to a three-year, $12 million deal. Jackson averaged 3.6 YPC over two seasons with Atlanta, totaling 1,250 rushing yards. 

• Detroit Lions signed Reggie Bush to a four-year, $16 million deal. Solid campaign in 2013 (1,006 rushing, 506 receiving, seven touchdowns) but useless by 2014. Released in 2015.

• Indianapolis Colts signed Ahmad Bradshaw to a one-year deal. Bradshaw cashed in for well over a million dollars on this one and while that's not a huge sum, it's more than a team should pay for a guy who only played in three games before a season-ending neck injury. Unpredictable? Not for a running back with an injury history.

• N.Y. Jets signed Chris Ivory to three-year, $10 million deal, and trade a fourth round pick to Saints for Ivory's services. Solid, albeit not very helpful three seasons from Ivory, who signed a $32 million deal with Jaguars in 2016. More on that later.

• Steelers signed Jonathan Dwyer to one-year, $1.3 million deal. Dwyer had 197 rushing yards and zero touchdowns for the Steelers that year.

• Tennessee Titans signed Shonn Greene to a three-year, $10 million deal. Greene had 687 rushing yards in two seasons.

• Jets signed Mike Goodson to a three-year, $6.9 million deal. Completely wasted money here. Goodson had seven carries for 61 yards after a PED suspension and before a torn ACL, MCL. Goodson never played again.

• Arizona Cardinals signed Rashard Mendenhall to one-year, $2.5 million deal. Mendenhall averaged 3.2 yards per carry and promptly retired.

That being said, there were some good bargains in 2013. That includes the San Diego Chargers, who signed Danny Woodhead to two-year, $3.5 million deal and he produced at a high level.

2014

• Kansas City Chiefs signed Jamaal Charles to four-year, $27.75 million extension. Made the Pro Bowl after barely topping 1,000 yards, but Charles has rushed for 404 yards over last two seasons while being paid over $13 million. 

• Cleveland Browns signed Ben Tate to two-year, $7 million deal. Played in eight games, averaged 3.1 YPC, was released, never played again after 2014. 

• Miami Dolphins signed Knowshon Moreno to one-year, $3 million deal. Final year of his career, had 31 carries. Torn ACL.

• Oakland Raiders signed Darren McFadden to one-year, $4 million deal. Averaged 3.4 YPC and scored two touchdowns over 16 games.

• Raiders signed Maurice Jones-Drew to three-year, $7.5 million deal. Had 43 carries for 96 yards. Deal only had $1.2 million guaranteed but it was a total waste.

• Steelers signed Blount to two-year, $3.85 million deal. Lasted 11 games and forced his way out of Pittsburgh to re-join Patriots.

• Jets signed Chris Johnson to two-year, $8 million deal. Made $4 million in 2014, rushed for one touchdown, was released.

• San Diego Chargers signed Donald Brown to three-year, $10.5 million deal. In two seasons with Chargers, Brown averaged 3.2 YPC and scored one touchdown.

• N.Y. Giants signed Rashad Jennings to four-year, $14 million deal. Released on Monday, Jennings scored 12 total touchdowns in three seasons, averaged 3.9 YPC.

There was a bargain of note with the Ravens and Justin Forsett. A low-key signing who made the Pro Bowl in 2014, Forsett is a great example of why you should search late-stage free agency for running backs and also why you shouldn't re-sign said bargains to big deals after they produce for you.

2015

• Philadelphia Eagles signed DeMarco Murray to five-year, $42 million deal. Murray had 702 rushing yards, 3.6 yards per carry in one season with Eagles, then was traded to Titans, where he renegotiated his deal.

• Ravens signed Forsett to three-year, $9 million deal. An incredible deal a year earlier, Baltimore gave Forsett decent money and in the next 13 games with the Ravens, he had under 800 yards and two touchdowns.

• Giants signed Shane Vereen to three-year, $13.25 million deal. Has scored one rushing touchdowns in 21 games, not an effective receiver in 2016 either.

• Eagles signed Ryan Mathews to three-year, $12 million deal. A much better bargain that Murray, Mathews has had 16 total touchdowns in two seasons but is also not capable of starting.

• Colts signed Frank Gore to three-year, $12 million deal. I'll admit that this freak of nature continues to produce. Not that the Colts have been a good team or anything though. 

• New Orleans Saints signed C.J. Spiller to four-year, $16 million deal. Played in 13 games with Saints, scored zero rushing touchdowns, caught 34 passes, and made $9 million.

• Saints signed Mark Ingram to four-year, $16 million deal. He is fine, but is not helping the Saints make the playoffs.

Best bargain of 2015: DeAngelo Williams signed a two-year, $4 million deal with the Steelers and has been a very solid backup. This is the type of free agent teams should covet: Really cheap, not over-used in previous stops, extremely talented. Of course, these types of running backs are really rare, which is why you should target the DeAngelo Williams you'd get in 2017 but instead are looking for the next version of him.

2016

• Tampa Bay Buccaneers signed Doug Martin to five-year, $35 million deal. Averaged 2.9 YPC and missed eight games.

• Jacksonville Jaguars sign Chris Ivory to five-year, $32 million deal. Averaged 3.8 YPC, missed five games, scored three touchdowns, rushed for 439 yards.

• Texans signed Lamar Miller to four-year, $26 million deal. Rushed for 1,073 yards, but YPC was down from 4.5 to 4.0 and his replacement Jay Ajayi was better.

• Broncos signed C.J. Anderson to four-year, $18 million deal. Missed nine games, YPC was down from 4.7 to 4.0.

• Dallas Cowboys signed Alfred Morris to two-year, $3.5 million deal. Averaged 3.5 YPC, had two touchdowns, which is what you should expect from a rookie day three pick, not someone in seven figures.

• Jets signed Matt Forte to three-year, $12 million deal and he averaged 3.7 YPC. 

• Dolphins signed Arian Foster to one-year, $1.5 million deal and he had 22 carries for 55 yards.

• Cincinnati Bengals signed Giovani Bernard to three-year, $15.5 million extension. Missed six games, had career-low 3.7 YPC, scored three touchdowns.

In 2016, the Patriots signed Blount for one-year, $1 million, which was a good deal. But they're not looking to give Blount a reward for helping them win the Super Bowl -- they're looking for the next lower-tiered running back who can help them for $1 million or less. Who is out there?

First of all, this Draft has a really special class of running backs. Headlined by LSU's Leonard Fournette, who could be the best running back prospect since Adrian Peterson (if not better, honestly), the depth goes way beyond that thanks to Dalvin Cook, Christian McCaffrey, D'Onta Foreman, Donnel Pumphrey, Curtis Samuel, Alvin Kamara, Wayne Gallman, Samaje Perine, the controversial Joe Mixon out of Oklahoma, and that's just the tip of the iceberg; if eight Pro Bowl running backs come out of this draft, it wouldn't be that surprising. 

That's one good reason to avoid Bell, Murray, Gillislee and Blount, but there are other options available to teams looking to upgrade at that position.

Many of the running backs already discussed here -- Jennings, Bush, Woodhead, Williams, Forsett -- will be available on the cheap. Other interesting affordable options include Christine Michael, Knile Davis, Terrance West, Dri Archer and many more. Perhaps Bell falls into that very exclusive category that only players like Lynch and Peterson deserve, but I wouldn't stretch that type of label onto anyone other than the type of player who comes around maybe once every five years. Even then, there's a chance that Bell, because of the dangers of playing running back and his history of suspensions, will be one of the worst decisions that the Steelers will make during this era. It's a trap that some other positions do not have, but Bell could be the rare running back who is worth the risk.

Teams have hopefully learned from the many mistakes made at that position in the past five years, but let's be honest … they almost certainly have not.