When drafting your fantasy football team, finding a true number-one running back isn't always easy. Yes, there are always a few safe plays at the position, but outside of the top prospects, choosing the right RB1 can be a tricky task.

This year there seem to be four truly elite options - Jamaal Charles, LeSean McCoy, Adrian Peterson and Matt Forte - who we have ranked in that order (you can learn more about our rankings by using our draft cheat sheet). Last season wasn't quite as nice up top.

One of the popular members of the pack being selected as a top-five pick a season ago was C.J. Spiller. Spiller was supposed to follow up his spectacular 2012 campaign in which he posted 1,703 yards from scrimmage and eight touchdowns with an equally dominant 2013, which is why many owners chose him as early as the second-overall pick. But fake footballers were left disappointed when the Bills' running back struggled his way through an injury-riddled season with only 1,118 yards from scrimmage and a pair of scores.

Unlike 2013, the former Clemson star is healthy coming into training camp this season. We know that a healthy Spiller has RB1 upside, but is he worth the risk? Let's take a look at what the numbers have to say.

Dominant When Healthy

Although he only missed one game last season, anyone who watched Spiller run knows that he wasn't 100 percent. C.J. would often come into the game, break a nice run and immediately limp off the field. Even with his ankle injury, he still managed to average a respectable 4.6 yards per carry last season, although it was his lowest since his rookie season.

Spiller struggled in a limited role in 2010 - his rookie season - but was nothing short of spectacular in 2011 and 2012. The Bills' star averaged 5.7 yards per carry on 314 carries, while adding 8.8 yards per catch on 82 receptions over that two-season span. Those are explosive numbers.

To get a better sense of just how good Spiller was in 2011 and 2012, here's a look at our Net Expected Points (NEP) data on him:

Year Rushes Rushing NEP Rushing NEP per Rush Receptions Rec. NEP Rec. NEP per Target Total NEP 2011 106 12.79 0.12 39 12.39 0.23 25.17 2012 207 25.45 0.12 43 22.34 0.39 47.79

Spillers' 107 carries ranked 50th among running backs, and his 39 receptions ranked 19th at the position in 2011. In 2012, his 207 rushes were the 22nd most in the league, while his 43 receptions were the sixth-most at the position. Let's compare his NEP numbers with other players who ranked in the same ballpark in terms of touches in 2011 and 2012:

Name Year Rushes Rushing NEP Rushing NEP per Rush Receptions Rec. NEP Rec. NEP per Target Total NEP Pierre Thomas 2011 110 19.36 0.18 50 20.72 0.35 40.08 Jonathan Stewart 2011 142 13.68 0.10 47 25.03 0.41 38.71 Fred Jackson 2011 170 3.77 0.02 39 23.77 0.48 27.54 Mike Tolbert 2011 119 -2.07 -0.02 54 27.28 0.35 24.25 Ahmad Bradshaw 2011 171 -0.74 0.00 34 14.79 0.34 14.04 Dexter McCluster 2011 113 -2.60 -0.02 47 14.91 0.23 12.31 Roy Helu 2011 152 -6.93 -0.05 49 10.98 0.18 4.05 Felix Jones 2011 128 -6.76 -0.05 33 8.53 0.19 1.77

For 2011, I looked at players who had between 100 and 200 carries who also added at least 30 receptions. There were eight such players other than Spiller. C.J.'s 25.17 Total NEP was fourth out of this group, behind Pierre Thomas, Jonathan Stewart and his own teammate Fred Jackson. With that said, his per touch stats were significantly more impressive. Although his receiving numbers are middle of the pack, the most impressive stat is his 0.12 Rushing NEP per Rush, which ranked second only to Thomas (0.18) out of this group.

The Bills' star was pretty good when compared to similar players in 2011, but blows his pier group out of the water in 2012:

Name Year Rushes Rushing NEP Rushing NEP per Rush Receptions Rec. NEP Rec. NEP per Target Total NEP DeMarco Murray 2012 162 -7.70 -0.05 35 10.91 0.26 2.53 Ryan Mathews 2012 184 -14.42 -0.08 39 8.67 0.15 -1.45 LeSean McCoy 2012 200 -14.73 -0.07 54 21.81 0.33 12.84 Mikel Leshoure 2012 215 -22.18 -0.10 34 8.60 0.18 -0.46 Darren McFadden 2012 216 -40.65 -0.19 42 3.16 0.05 -13.17 Matt Forte 2012 248 2.43 0.01 44 12.00 0.20 -8.54 Reggie Bush 2012 227 -9.47 -0.04 35 21.82 0.42 8.52

For 2012, I looked at players with between 150 and 250 carries and at least 30 receptions, as Spiller saw more volume that year. This list included seven players, all of whom (other than Mikel Leshoure) have posted at least one 1,000-plus yard rushing season in their career. Spiller had a better Rushing NEP, Rushing NEP per rush, Reception NEP, Reception NEP per target and Total NEP than all of them. In fact, Spiller's massive 47.79 Total NEP was a whopping 34.95 better than LeSean McCoy's, who was the next best in this group. Although his numbers during an injury-filled 2013 weren't there, don't forget just how dominant he was in 2012.

Spiller's Risk

Whether it was due to health or not, Spiller had an incredibly down year in 2013. Among the 28 running backs with 175 or more carries, Spiller's -12.74 Rushing NEP ranked 18th within the group. What's worse - and probably most telling about his season - was that his Success Rate ranked second-to-last among the 28 running backs. (Success Rate measures the percentage of runs that contribute positively towards a player's NEP.)

Considering this low Success Rate score, it appears as though the biggest reason Spiller didn't rank lower in terms of Rushing NEP was because of his big-play ability - a couple of big runs, and his Rushing NEP skewed favorably. In fact, the two players who ranked next to Spiller in Rushing NEP were at least five percentage points better in Success Rate last year. His reliance on the big play was evident, and that's a major risk.

But in addition, probably the biggest detractor from Spiller's fantasy value is the fact that the Bills give the ball to Fred Jackson just as often as they give it to Spiller. As Leo Howell pointed out in his recent article profiling Jackson, only 10 of the 22 backs who carried the ball 200 or more times finished with a positive Rushing NEP last season. Jackson finished fifth in that group, and Spiller wasn't part of it.

Not only does Jackson get just as many touches (Jackson had 253 touches from scrimmage last season compared to Spiller's 234), but he's also the Bills' back who gets the ball at the goal line. Last season, the Bills converted 15 rushing touchdowns. F-Jax accounted for nine of them, only two of which came from outside of the five yard-line. Meanwhile, Spiller only accounted for two of Buffalo's 15 rushing touchdowns, both of which came from outside of the red zone - a 54-yard run against the Browns and a 36-yard run against the Falcons.

Freddy isn't the only other back Spiller has to compete with this season, either. The Bills traded for talented former Eagles' running back Bryce Brown this offseason, and all reports out of Bills camp say they plan on using him. They wouldn't have given up a fourth round pick that could turn into a third rounder if they didn't. You can read more about that situation here.

The good news for Spiller, Jackson and Brown is that the Bills ran the ball more than any other team in the league last year under coach Doug Marrone, seeing 546 rushes, a whopping 37 more rushing attempts than Seattle (who had the second most in the league). Buffalo's pass-to-run ratio ranked as the third run-heaviest. With a young quarterback and young passing game weapons, there should still be plenty of touches to go around in the Bills' backfield.

Is Spiller Worth the Risk?

There are plenty of risks surrounding C.J. Spiller: Can he stay healthy the entire season? Will he score enough touchdowns to have serious fantasy value? Will Jackson and Brown take too many touches for Spiller to be a fantasy starter? Was 2013 - where he ranked

As a high-risk, high-reward commodity, he currently ranks 28th at running back in our preseason projections, as the projections take everything - the good and the bad - into consideration. But by using our confidence interval (CI), you can see that his high-end within the interval sits at about 171 points, which firmly makes him an RB2. We're not in the game of predicting another historic 2012 season from Spiller, but we can understand teams wanting him as their RB2 if their drafting mostly for upside.