Should the Texans be searching for Arian Foster's replacement in the draft? And should that make fantasy owners skittish?

Playing fantasy football is a lot like investing in the stock market. The balancing act between measuring risk and reward can be unnerving.

In bull markets, you can do no wrong. In bear markets, you try and hedge your bets with slow but steady performing stocks. Sometimes markets are wildly unpredictable, with the Dow experiencing gains and losses of multiple percentage points, multiple times within the same week. Investing in high-risk, high-reward stocks, particularly if you havenâ€™t hedged your bets, is not for the faint of heart.

Such is the life of an Arian Foster owner and, likely, Houston Texans coaches as well. Since 2010, Foster has put up staggering raw numbers accumulating, 6,052 rushing yards and 50 rushing touchdowns over this time frame, while being widely recognized as one of the most productive running backs on the field when healthy.

But thereâ€™s the rub. Fosterâ€™s raw rushing numbers seem even more impressive when you account for the fact that, since 2010, heâ€™s missed a total of 15 games. Fosterâ€™s injury history has prompted coach, Bill Oâ€™Brien, to acknowledge that the Texans have to manage Fosterâ€™s workload better in 2015, leading to speculation that the Texans may begin searching for his replacement in the draft this year.

numberFireâ€™s metric of determining player productivity, Net Expected Points (NEP), allows us to analyze player efficiency in a way that de-emphasizes touchdown production. To put it differently, each situation on the field has a given point expectation. If a running back faces a 3rd-and-4, and they rip off a 10-yard dash, then he has extended the drive and positively contributed to his teamâ€™s point total by increasing his teamâ€™s chances of scoring, thus positively contributing to his own Rushing NEP. You can read more about NEP in our glossary.

So what do the numbers say about Fosterâ€™s productivity on the field, as well as the urgency the Texans should place on finding his replacement in this yearâ€™s draft? And, for fantasy owners, is the risk of drafting Foster worth the potential reward, even if his carries are managed in 2015? Follow me and weâ€™ll find out.

Bull Rushing

To get a sense of Fosterâ€™s effectiveness in comparison with running backs who get a respectable workload, Iâ€™ve compiled rushing efficiency statistics from 2010 to 2014 for each running back who amassed at least 120 rushing attempts in a given season. Since 2010, Fosterâ€™s per-rush performance has been, at-worst, league average, and at best, near the top of the class.

Foster Rushes Rushing NEP Rushing NEP/P Rank Success Rate Rank 2010 326 27.90 0.09 3 of 39 46.63% 8 of 39 2011 279 -3.60 -0.01 20 of 38 43.73% 11 of 38 2012 351 -6.68 -0.02 15 of 31 41.88% 18 of 31 2013 121 0.52 0.00 18 of 40 43.80% 18 of 40 2014 260 8.51 0.03 9 of 38 39.23% 25 of 38

After a blazing start to his career, Foster fell back down to earth a bit in 2011 through 2013, with his huge fantasy numbers in 2011 and 2012 being largely attributable to volume. During these seasons, Fosterâ€™s Success Rate, the rate at which his rushes positively contributed to his NEP, was largely stable between 42% and 44%. That said, his Success Rate rank in comparison with his peers slipped in 2012 and 2013.

But in 2014, while not quite the beast he was in 2010, Foster was still really impressive on the field, compiling the ninth best Rushing NEP per rush behind the 23rd best offensive line, according to Football Outsiders' offensive line rankings. But Fosterâ€™s rushing success rate also dipped below 40% for the first time in his career, suggesting that his impressive per rush efficiency was attributable to breaking off big runs. And as was the case for Doug Martin, this tendency to break off the home run scamper isnâ€™t always transferable from season to season.

But Fosterâ€™s rushing numbers donâ€™t fully reflect his true productivity. Fosterâ€™s ability to serve as a three-down back is significantly buttressed by his efficiency in the passing game.

Foster Receptions Reception NEP Reception NEP per Target Rec NEP/Tar Rank 2010 66 40.68 0.48 8 of 39 2011 53 34.39 0.48 6 of 38 2012 40 3.38 0.06 29 of 31 2013 22 7.12 0.20 23 of 40 2014 38 27.28 0.46 5 of 38

While regressing in efficiency in 2012 and 2013, Foster returned to his near top-of-the-class receiving prowess on a per-target basis in 2014. In fact, Fosterâ€™s efforts in the passing game contributed to his finishing fifth in Total NEP among backs with at least 120 carries, besting the likes of Eddie Lacy and DeMarco Murray, both of whom were drafted earlier than Foster in 2014 fantasy leagues. Both of these players also played in 16 games -- compared to Fosterâ€™s 13.

So, with Fosterâ€™s re-emergence as a top-flight all-purpose back in 2014, do the Texans have some breathing room in seeking out his replacement in this yearâ€™s draft? The answer, sadly, is probably not.

The Downturn

With Foster out three games, and largely unused in a fourth game last year, Alfred Blue served as his primary stand-in, amassing 170 carries, providing us with a sample size large enough to render at least some judgment on his abilities. The results? Not pretty.

Rushes Rush NEP Rush NEP/P Rank Rec Rec NEP Rec NEP/Tar Rank 170 -21.20 -0.12 34 of 38 18 8.09 0.53 4 of 38

Blueâ€™s efficiency on a per-rush basis (-0.12) was atrocious in 2014, besting only a handful of numberFireâ€™s Hall of Shame luminaries, including Darren McFadden (-0.15) and Andre Ellington (-0.14). Blue effectively lost 21 expected points for the Texans due to his lack of efficiency. While he did show skills in the passing game, registering a higher per target NEP (0.53 on 18 targets) than Foster (0.46 on 59 targets), it remains to be seen whether this can continue into next season.

The other Texans running back, Jonathan Grimes, has received 60 carries combined over the past two seasons, so itâ€™s tough to judge him with confidence one way or another. In 2013, he was very effective with a mere 21 carries, compiling a 0.06 Rushing NEP per rush. But in 2014, this progress was undone and then some, as Grimes regressed to a near Alf Blue level of inefficiency (-0.08 Rushing NEP per carry) on slightly more carries (39) than the previous season.

Suggesting that Grimes canâ€™t be a legitimate backup based on his performance in 2014 is probably premature, but his performance certainly doesnâ€™t inspire confidence that heâ€™d be able to pick up where Foster left off if an injury sidelined him for a sustained period of time.

Playing the Market

In the upcoming draft, the Texans staff might decide itâ€™s best to address some of their offensive line woes early in the draft as a two-fold strategy. First, Foster would likely be less dependent on big runs to contribute positively toward the teamâ€™s expected points. Secondly, Fosterâ€™s heir will also benefit from young top-grade talent creating holes for him to run through for years into the future.

With Foster under contract through the 2016 season, the Texans may not have to invest a first round pick in a running back. But itâ€™d be foolish on their part to neglect the position all together in the draft. At the very least, the Texans should consider taking a flier on a back that theyâ€™re reasonably certain will outperform Blue or Grimes. That way, if the all-too-familiar injury bug strikes Foster sometime in 2015, theyâ€™ll at least have the potential of a back who can put up a positive NEP season. In this instance, theyâ€™d be able to capitalize on Blueâ€™s ostensible effectiveness in the passing game while avoiding all of his inefficiencies when accepting handoffs.

Luckily for fantasy owners, the NFL draft is right around the corner, so they can see how the Texans play their hand regarding Fosterâ€™s replacement before they draft their fantasy squads. But even if the Texans spend an early round draft pick on a running back, donâ€™t expect Foster to get placed in a 50/50 timeshare.

Foster was too good in 2014 to be ignored, so even if managed to 15 to 20 carries a game, heâ€™ll still put up more than worthy fantasy numbers. Just make sure that you handcuff him on your squad with his heir apparent if the Texans do go that route in case Foster gets sidelined for a few games.

Fantasy owners can be skittish and sensitive, just like the stock market. Thus, with a history of injuries and rumors of his replacement coming to Houston, Foster represents a top-end player that you can probably get in the mid-second round come draft day, who, if healthy, is a near lock to put up first round numbers. Now thatâ€™s what I call a market in need of a correction.