A couple of years ago, some friends and I went to a Big Brothers Big Sisters bowling event to raise money for the program. We all bowled two games, and the highest single game of any bowler at the alley would be crowned winner, getting a trophy to proudly display on their desk at work.

My friend bowled a 202. He won.

While it was certainly an accomplishment, I don’t know if he was ready for what was to come. It’s not as though we go bowling all the time, but if and when we all did, the expectation would be for him, Mr. 202, to always win.

He didn’t.

His 202 was unbeatable on that Big Brothers Big Sisters day, but it wasn’t the norm. It just happened to occur at the right time. It was one of the first instances we had ever seen him bowl, so our perception of his game was that he was some sort of closet professional. And to be fair, it wasn’t all that outlandish of a thought – the dude went to the bowling alley with his own ball and shoes! (We later found out that he bought them at a garage sale the week before.)

His story is like that of Chris Johnson’s. The now ex-Titan running back did what only a handful of running backs have ever done in just his second year in the NFL, rushing for over 2,000 yards while accumulating over 2,500 yards from scrimmage. But that became the Chris Johnson expectation. That was how football fans perceived him. He was a speedy back who was capable of doing more than any other runner in the league.

That’s not how things played out. Just like we saw my friend regress to his 130 bowling average (he does have a sweet ball though), we’ve watched Chris Johnson – over the last three to four years – become, well, average. And in fact, when you look at the analytics, Chris Johnson may not even be that. Chris Johnson may be a bad running back.

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We live in a fantasy football-driven NFL (world?), and when we look at Chris Johnson’s numbers through that fake pigskin lens, we tend to see a decent runner. He’s never totaled fewer than 1,400 total yards in a season, and while his 2011 campaign watched him score just four times, he’s tallied double-digit scores in four of his six seasons in the league. At a quick glance, he’s not that bad.

At a deeper glance, he’s not that great. At numberFire, we use a football metric called Net Expected Points (NEP), which looks at down and distance and game situations to give a real value to the offensive players on the field. To read more about the statistic, click here.

It’s difficult for running backs to really make an impact within the metric, as it’s difficult to gain large chunks of yards when you’re pounding it between the tackles. But when you compare running back Rushing NEP scores within the position, you can start to gauge how effective or ineffective a particular runner is or was.

I’ll give you the raw numbers first. Chris Johnson’s totals over his six seasons in the NFL can be found below:

Anytime you’re dealing with metrics and you see a negative number, you know it can’t be a good thing. And in Johnson’s case, it isn’t. He’s had just one season where his Rushing NEP total has been greater than zero, while the other five have seen him lose about 15 to 20 points for the Titans.

But like I said, it’s difficult for running backs – especially high-volume ones – to see significant values within this metric. And actually, his 2009 campaign shouldn’t be overlooked, as it was the 17th-best running back season we’ve seen since 2000.

That’s also part of the problem. How can a player who rushed for 2,000 yards only barely rank in the top 20 among running back seasons over the last 15 years? Because he lacks efficiency. He’s getting his totals on volume.

Anyone who’s watched the NFL since Chris Johnson entered the league knows that he sees numbers because he’s consistently seen a high workload in the NFL. Since 2008, the year he entered the league, only Adrian Peterson has had more carries than Chris Johnson (1,795 vs. 1,742). And there’s a significant 161-carry gap between Johnson and the number three player on the list, Steven Jackson.

The difference between Johnson and these other bulk carriers is that they’ve been able to sustain efficiency, while Johnson hasn’t. Below is a chart of the seven other high-volume running backs that we’ve seen since Johnson has entered the league, showing the percentage of seasons where they had a positive NEP total, as well as their median Rushing NEP score throughout their careers.

As you can see, while many of these runners have negative median scores, they’re not even close to as bad as Johnson’s. And moreover, nearly every running back has seen a positive Rushing NEP total in a quarter of their seasons, while Johnson sits at a not-so-good 16.67%.

I know I keep saying this, but it’s not easy for running backs to contribute positively in terms of NEP (it’s a logical thing if you’re correctly comprehending what NEP is). But Chris Johnson’s score is so much lower than any of his peers who have been high-volume runners, and that's alarming.

Even when you look at every 200-plus carry season from a running back since the year 2000, Johnson’s standard season doesn’t come close to being top-tier runner-like. Over this time, we’ve seen 328 of these seasons. The worst came from Eddie George in 2001, where he compiled a Rushing NEP total of -66.88. If you recall, that was the year he had over 300 rushing attempts and didn’t even break 1,000 yards on the ground. And although that -66.88 number looks far off from Chris Johnson’s -20.55 median, it’s not. A typical season from Chris Johnson gives you production similar to the 250th-ranked running back on that list of 328. In other words, among all high-volume runners, a Chris Johnson season won’t even reach the 25th percentile in terms of effectiveness.

Let that sink in for a second. There have been some bad 200-plus carry running backs since the year 2000. We saw Travis Henry, Duce Staley, Chris Brown, Domanick Davis, Tatum Bell – the list goes on and on. And the majority of these seasons were better than what the Titans got out of Chris Johnson.

To give you a good reason as to why this is the case, we can use our fancy Success Rate metric. Essentially, Success Rate for running backs looks at the percentage of rushes that contribute positively towards a player’s Rushing NEP. If, say, a guy runs for a first down, that’s deemed a success. If he pulls a Chris Johnson and gets tackled seven yards behind the line of scrimmage, then, well, that’s a failure of a run.

We all know that Chris Johnson is a boom or bust type of runner, and that’s exactly what the Success Rate measure shows us. Over the course of his career – over 1,700 rushing attempts – Chris Johnson has average a 39.03% Success Rate. To put this another way, you’d expect 39 out of every 100 rushing attempts from CJWhateverK to produce a positive NEP outcome.

That’s a problem. Looking back at our 328-player sample of 200-plus attempt seasons, Johnson’s Success Rate, just like his Rushing Net Expected Points median, ranks in the bottom quarter percentile. To give you an idea of how bad that type of Success Rate production is, a 39.03% rate was a bottom five number out of the high-volume runners (22 of them) in 2013.

It’s not just the rushing metrics that I’m worried about here, either. There’s a statistic we use called Reception Net Expected Points per target, which looks at the number of points added on receptions only - through the air - and divides it by volume. It’s a nice way to find how efficient a player is when catching the football.

Since 2000, the average Reception NEP per target score among 35-plus reception running back seasons (Johnson has caught at least 35 passes in each of his NFL seasons) has been 0.33. Johnson has surpassed this number just twice, and averages a Reception NEP per target of 0.23. To give you more context, Johnson’s efficiency through the air throughout his career would have tied him for the sixth-worst average among the 26 runners with 35 or more catches in 2013.

Though he’ll catch 30 to 50 passes a season, he doesn’t do a whole lot with the receptions. It’s just another example of why he’s been fortunate to see a lot of volume.

Will He Work in a Different Uniform?

I can’t stress enough how overrated Chris Johnson is as a running back in the NFL. Literally, the only thing that he has going for him is the fact that he can stay healthy. But a lot of that has to do with the fact that he avoids contact, which is part of the reason his numbers are so, so poor.

It’s no surprise that teams haven’t been insanely interested in giving Johnson a roster spot. He’s not a true lead back, and the perception that surrounds him is completely inflated by one truly good season. And even that season, while historic in raw number form, wasn’t as good as those numbers indicated.

While I can see him working with a team like the Jets or Falcons in a tandem role, my expectations for Johnson from here on out are about as high as what they are for the movie Draft Day. And that’s not good.