Why We Shouldn't Be Optimistic About Arian Foster's Future in the NFL

Arian Foster has had an amazing career.

I say that in past tense because, well, I'm not all that optimistic about his future in the league.

It wasn't a surprise move, but today, the Houston Texans released their well-known running back.

Foster's been in the league since 2009, and he's produced four 1,200-plus yard rushing seasons. But there are a few things working against him: he'll be 30 years old when the 2016 season starts, he's coming off a major injury, and the running back market is fruitful.

Things aren't exactly looking up.

A Problematic Decline

Arian Foster hit a wall last year.

According to our Net Expected Points (NEP) metric, which measures how well a player performs above or below expectation (you can read more about NEP in our glossary), Foster was really, really bad in 2015. Like, Fuller House bad.

The sample isn't massive thanks to an Achilles tear that ruined his season -- more on that in a bit -- but among the 72 rushers last year with 50-plus attempts, Foster's Rushing NEP per rush rate was second worst, ahead of only Tre Mason. To put this another way, Foster was contributing less for his team with each tote than nearly every single relevant running back in 2015.

If you recall, Foster tore his groin muscle off the bone during his first padded practice over the summer. He was able to return during Houston's fourth game, but the numbers show that he just wasn't the same. He wasn't the same at all.

Take a look at the chart below that shows his Rushing NEP per rush rate versus the league average during his years as a pro. His 2015 campaign is startling.

Over his career and prior to last season, Foster never dipped below the league average Rushing NEP per rush rate. Last season, though, the league average was -0.01 (rushing is less effective than passing, hence the negative number), and Foster produced at a -0.24 Rushing NEP per rush rate.

However, it should be noted that Foster fumbled at a much higher rate last year than in year's past. With so few carries, that certainly skews things a tad -- he lost 7.56 Rushing NEP on fumbles, and without them, his Rushing NEP per rush rate goes from -0.24 to -0.12.

But that's still far below the league average.

To be honest, we can get past the ineffectiveness of 2015. It's one year, the sample is small, and he was coming off a major groin injury.

What I can't get past, though, is something that's been changing over the last couple of seasons. And that's his Success Rate.

Rather than looking at per rush efficiency, we can also look at what percentage of runs contribute positively towards a running back's overall NEP -- we can look at a running back's rate of success.

Foster was a monster early on in his career because he had both a high Rushing NEP per rush average while maintaining a high Success Rate. In other words, he was more than likely breaking some big plays, which help his Rushing NEP per rush, but he was also grinding out every single run, aiding in a high Success Rate.

If his Success Rate stayed steady through the years while his Rushing NEP per rush declined, I'd dig a little deeper and probably credit that to fewer big plays. That'll happen as you age at the running back position.

The problem with Foster, though, is that his Success Rate has diminished to be below average over the last two seasons (sub-40%), all while his per rush efficiency has fallen, too.

The plays boosting his Rushing NEP per rush are gone, and he's not picking up successful plays at a high rate.

That's not good.

And that's not all.

An Impossible Injury Comeback?

I mentioned that Foster tore his groin muscle off the bone last summer, but what actually ended his season was an Achilles tear.

We haven't really seen an elite running back -- at least in the Internet age -- tear his Achilles. It's always been borderline backs like Mikel Leshoure or Kendall Hunter.

The number of backs who have suffered the injury is small, too, but it's still very worrisome. Because none of the backs have been able to return to full health afterwards. None. 

We've seen success stories at other positions -- Demaryius Thomas being one of them -- but running backs haven't been successful. That doesn't bode well for a guy who's going to be 30 in August.

Foster's Future

Apparently Foster will be ready for camp, but even if he is, it's hard to imagine he'll be 100% healthy. 

It's not like there's no competition in the free agent running back pool, either, with players like Doug Martin, Chris Ivory, Lamar Miller, Alfred Morris, Bilal Powell, LeGarrette Blount, and Matt Forte out there for teams to sign, let alone a draft coming up in May.

What's the point in adding a declining player who's coming off an injury no single running back has ever successfully come back from?

To me, it's simple. We've seen the best of Arian Foster, and we may have seen the last of Arian Foster.

I hope it's not true just as much as you do.