Chris Johnson earns biggest RB contract ever. Is he worth it?

Chris Johnson is now the highest-paid running back in the history of the NFL after receiving a four-year, $53.5 million contract extension with the Tennessee Titans, with $31 million of it guaranteed. But was that a wise investment? Johnson is only 25 years old (26 in a few weeks), and is only two years removed from a spectacular 2009 season in which he collected 2006 yards. But “only” is a relative term when talking about the NFL. It’s not impossible to think he’s already at the midway point of his career, and considering his yard and touchdown totals dropped substantially in 2010, who knows how good he’ll be five years from now.

Contracts to big-time running backs almost never work out; in fact, the failure rate may even be higher than the failure rate of big-time pitching contracts. With baseball, the sport can be such an enigma at times that it isn’t surprising when pitchers like John Lackey and Carlos Zambrano “lose their stuff” after years of success. With football, it’s a very different reason. Running backs have an incredibly short lifespan, maybe even shorter than tennis players. In a position completely dependent on speed, it’s very rare for a running back to be productive after the age of 30, and even rarer that a team won’t demote them to second- or third-string in lieu of a younger, fresher back with less miles under his belt. Cedric Benson, at 28 years old, is the oldest first-string running back in the league.

That’s only two years older than Chris Johnson.

The line between being in your prime and being washed up is remarkably thin, which is why giving large contracts to players with such a short life cycle rarely works out. Priest Holmes was 30 when he had a fantastic season for the Kansas City Chiefs, rushing for 1,420 yards and setting a new single-season touchdown record of 27. For his efforts, he was given a four-year extension worth $35 million. Holmes never again rushed for 900 yards in a season. The man who broke his single-season touchdown record was Shaun Alexander, who collected 28 TD’s and 1,880 yards in 2005. Alexander, who was 28 at the time, signed a gargantuan eight-year, $62 million deal with the Seahawks that offseason (although only $15 million was guaranteed). Alexander was almost identical to Holmes after his deal, playing in three more seasons and never even accruing 900 yards.

And the man who broke his record was LaDainian Tomlinson, who collected 31 of them in 2006. However, Tomlinson had already earned his big pay day ($60 million, $20 million guaranteed in 2004) when he had his best season in 2006, unlike Holmes and Alexander, who had their big contracts after their sensational seasons. So clearly there are exceptions to the rule, just as pitching contracts to Greg Maddux and Tom Glavine in Atlanta worked out fine, whereas, say, big contracts to A.J. Burnett and Carl Pavano in New York weren’t nearly as successful. Keeping with the age theme, Tomlinson was 25 when he signed his big deal and 27 when he set the record. He’s only had two 1,000-yard seasons since.

Aesthetically, it’s hard to see Chris Johnson deservedly earning his $31 million. In may ways Tomlinson was an outlier. He had a longer lifespan than most and succeeded after his big deal because he really was one of the greatest running backs ever, whereas Alexander and Holmes were a flash in the pan. But Tomlinson is the best case scenario. Handing out a “good” contract to a running back requires not only foresight, to see if the player really is good enough to sustain the production, and not only good timing, as running backs start to degrade once they’re around 28, but luck. After all, who’s to say that Johnson can’t be derailed by a series of fluke injuries, ala Brian Westbrook?

The bottom line is that none of us know what to expect from Chris Johnson. The good news is that he’ll be 26 years old this year, so if we’re going by the book, he should at least be serviceable for a few more seasons. But none of us know if he’s really a Hall of Fame talent, which is ultimately the distinguishing factor in not only why Tomlinson’s contract worked out and why Alexander’s and Holmes’ didn’t, but why contracts to pitchers like Roy Halladay and Tim Lincecum work out, but deals to Daisuke Matsuzaka and Jamey Wright go horribly awry. The discrepancy between running for 2,006 yards and 1,364 yards is gigantic, and while there isn’t anything concerning about a 1,364-yard season -- which is still great -- it’s an awfully large drop-off for someone whose numbers you’d expect to go up in the middle of his prime. If we see 2,006-yard Chris Johnson again this season, there’s no question he was right in earning the largest halfback deal in history. If it’s 1,364-yard Chris Johnson however, it may be time to question it. If we really have already seen his best season, it isn’t appropriate to ask if he isn’t another Priest Holmes or Shaun Alexander. Time will tell.