How to value Panthers RB tandem

Are Jonathan Stewart and DeAngelo Williams unstartable in fantasy because they are teammates?

There's no question that the Carolina Panthers know how to run the ball. Since 2008, when DeAngelo Williams took over as the team's No. 1 rushing option and Jonathan Stewart stepped in as the "change of pace" No. 2 running back, the team's ground attack has consistently been one of the best in all of football. The numbers speak for themselves:

Carolina Panthers Rushing, Past 4 Seasons

The struggles of 2010 were a bit of an anomaly, primarily because Williams hurt his foot and needed to be placed on injured reserve after only six games. Jonathan Stewart also got hurt during the season, missing several weeks with a head injury. Few teams would be able to post solid numbers when forced to go that deep on their depth chart.

Healthy again in 2011, the combination of Williams and Stewart once again ran roughshod over the league. Carolina has an incredibly solid offensive line, anchored by Pro Bowl center Ryan Kalil, which helped the Panthers' rushing attack, spearheaded by their dynamic duo, to lead the NFL in 2011 with 5.4 yards per carry.

So why aren't fantasy owners salivating over Williams and Stewart? Part of the problem is that while the numbers they post together are incredibly impressive, taken separately you never know which one of the two is going to be the one to start in any given week.

In 2011, Stewart had six games with double-digit carries, and no more than 14 in any single week. Williams had nine games of double-digit carries, with no more than 15 in any given week. Stewart had seven games in which he scored double-digit fantasy points and Williams had six.

Combined, the two backs would have finished No. 3 overall among running backs, behind only Ray Rice and LeSean McCoy in ESPN standard scoring. As it stands, Stewart ended the year with 133 points, good enough only for 25th overall at the position. Williams was five points behind his teammate at No. 26. Even in a 12-team league, neither back earned enough points to be considered worthy of starting regularly in a two-RB lineup.

On their own, either player would be far more valuable. Together, neither one does enough.

In terms of touchdowns per touch, among all players with at least 100 touches (rushes plus receptions), Williams ranked 16th overall, and Stewart was a little bit further back at 33rd on the list. Unfortunately, both played on a team with quarterback Cam Newton.

Not only did Newton score 14 touchdowns from scrimmage, far and away the most from any signal-caller -- Mark Sanchez and Tim Tebow tied for second on the season with six each -- but his prolific scoring, one every 9.1 touches, was the highest rate of any NFL player last year. Not only did Williams and Stewart get in each other's way in terms of scoring opportunity, but with Newton's legs entering the equation, the available pie got a whole lot smaller.

In 2012, that pie will get smaller still. Mike Tolbert, who ended last season with 137 fantasy points, one spot higher than the Carolina duo, signed with the team in the offseason as "insurance." Tolbert could easily get some looks in the red zone, as he ranked No. 8 in touchdowns per touch last season and had seven scores on rushes from inside the 10-yard line. (Cam Newton had nine such scores, while Stewart had three and Williams only two.)

They say that two heads are better than one, but when it comes to Carolina's backfield, "Double Trouble" is simply too much of a headache to put up with on a weekly basis. Sure, at the end of the season the combination of backs should once again elevate the team's rushing game into one of the fiercest ground attacks in the league, with or without Cam Newton's contributions taken into consideration.

However, while the Panthers may give you more than 100 yards and two rushing scores per game all season long, it's not always going to come from any one source. Start Stewart one week, and that's the game he goes for just 20 yards, while Williams rushes for 115 yards and a touchdown. Go with the hot hand the next week and shake your head sadly as Stewart outscores his teammate 12-4.

It's been that way before and it will be that way again. Unless and until one of these backs gets traded or chooses to leave via free agency for greener pastures, neither Williams nor Stewart can be relied upon on a regular basis as anything more than a roll-of-the-dice play. For now, selecting either back in the first two dozen picks at the position -- starter level in a 12-team league -- is sheer folly.