Making Sense of the San Diego Backfield: Donald Brown's Impact

Can you really trust Ryan Mathews to be the bell cow of the San Diego backfield in 2014?

At times during the 2013 regular season, the San Diego Chargers caught lightning in a bottle - both literally and figuratively - seeming to finally overcome a previously enigmatic offense. Behind first year head coach Mike McCoy, Philip Rivers had a top-five quarterback season, and the Chargers featured a balanced attack, passing the ball 52.82% of the time, down from 2012 and 2011.

In turn, the dynamic backfield duo of Ryan Mathews and Danny Woodhead led the Chargers backfield to the eighth-ranked rushing attack according to our adjusted (for strength of schedule) metrics.

With the Chargers running back success in 2013, it was certainly surprising to some that the team added Donald Brown via a three-year, $10.5 million contract in March.

So for starters, let's first examine why the Chargers added Brown. While he analytically had the best rushing season in his career last season, Ryan Mathews hasn't proven to be durable, managing to play 16 games for just the first time in his career a season ago. He did suffer a high ankle sprain late in the season, and that certainly impacted the Chargers game plan in the playoffs. Additionally, both Mathews and Woodhead are unrestricted free agents at the end of the 2014 season, so the move seems to be somewhat focused on 2015, but also provides quality depth this year as well.

But if you're a fantasy football player looking to make sense of the Brown signing, it seems to muddy the waters and crowd the Chargers backfield even more, especially when Chargers' GM Tom Telesco said in March that Mathews is still the Chargers "bell cow".

From a football perspective and using numberFire metrics, the Chargers signed Brown because he was, well, darn good last year, and can do many things on the field well when he's in the game. Here's a look at how the Chargers new 2014 backfield looks in terms of 2013 Net Expected Points for running backs with over 75 carries:

2013CarriesRushing NEPRushing NEP/RushReceptionsReception NEP
Mathews2855.77 (13th)0.02 (15th)2612.26 (22nd)
Woodhead106-4.35 (25th)-0.04 (27th)7649.43 (2nd)
Brown10213.91 (6th)0.14 (2nd)2714.6 (19th)

Brown's Rushing NEP of 13.91 ranked sixth among the 55 running backs with at least 75 carries last year, and his per rush efficiency was even better, ranking second overall with a Rushing NEP/Rush of 0.14, behind only James Starks. To add to this, Brown only had four rushes of 20 plus yards, so his Rushing NEP showed that Brown was really good at getting sizable chunks of yardage every time he rushed, even when he wasn't hitting a home run. In fact, his Success Rate, which measures the percentage of rushes that translate into positive NEP gains, ranked fourth among this group of 75-plus attempt rushers.

Mathews' Rushing NEP of 5.77 ranked 13th, and on a per rush basis, he ranked 15th. Considering Mathews was one of the highest-volume backs last season, his positive score is excellent. Danny Woodhead's receiving metrics are where he made a name for himself a season ago, finishing second in Reception NEP only behind Jamaal Charles. While Woodhead has traditionally been thought of as a "third-down back", it may surprise you that, according to Pro-Football-Reference, of Woodhead's 106 carries in 2013, only four (4%) were on third down. And 21 of his 87 targets (24%) were on third down. So considering his size and the surprise element of Woodhead running the ball, his -4.35 Rushing NEP (ranked 25th) and -0.04 Rushing NEP/Rush (ranked 27th) actually displays Woodhead's running ability on downs when defenses are expecting more running plays.

All of this is to say that the Chargers now have three pretty efficient running backs - at least in terms of 2013 numbers. Does their historical production paint as nice of a picture?

2012CarriesRushing NEPRushing NEP/CarryReceptionsReception NEP
Mathews184-14.42 (41st)-0.08 (36th)398.67 (26th)
Woodhead757.1 (9th)0.09 (3rd)4041.67 (1st)
Brown108-5.97 (25th)-0.06 (31st)94.21 (39th)

2011CarriesRushing NEPRushing NEP/CarryReceptionsReception NEP
Mathews2224.54 (14th)0.02 (18th)5029.06 (5th)
Woodhead778.29 (11th)0.11 (5th)188.97 (31st)
Brown1349.76 (9th)0.07 (10th)162.09 (51st)

From the table, the 2012 year highlights that Woodhead was first in Receiving NEP among all of the 54 running backs with 75 carries or more, and was extremely efficient with a Rushing NEP of 7.1 (9th) and a Rushing NEP/Rush of 0.09 (3rd). He posted nearly identical rushing stats in 2011 as well, with significantly less action in the passing game. Though he's been fortunate to play in highly effective offenses, Woodhead certainly is a worthwhile running back to get involved, especially through the air. He's just not a volume player given his size.

Mathews' 2012 was abysmal and injury riddled, compiling a Rushing NEP (-14.42) that ranked 41st out of 54 running backs. However, Mathews had a solid and underrated 2011, posting a Rushing NEP of 4.54 (14th out of 64 running backs with 75 plus carries), similar to 2013. And his season on a per rush basis was identical to 2013 as well.

Lastly, Brown, who basically replaces Ronnie Brown on the depth chart (Ronnie Brown had 45 carries and 8 catches last season and didn't do much with them), has had two very efficient campaigns over his last three seasons. He's mostly played in a committee during this time (to be fair, his whole career), but this sheds light as to why San Diego wanted him as part of their committee - he can be very effective.

Given historical context, it seems as though Mathews is certainly still the candidate to receive the bulk of the carries in San Diego, while Woodhead continues to be their top receiving back. Brown can do a little bit of both, but given his efficient ground game play, he may take more away from Mathews than Woodhead in terms of carries. That's only natural though, as Mathews topped his career high by 63 attempts a season ago.

Brown will more than likely assume all of the 45 carries that Ronnie Brown had last year, and could easily grab another 50 or so. While this is certainly a hit to Mathews' fantasy value, it should allow him to stay healthier, all while continuing to see over 200 attempts. If he performs like he did in 2013, he'll still be efficient enough to stay relevant.

While none of these running backs will be selected incredibly early in fantasy drafts, they each have value of some sort. And if the Chargers continue to pound the ball as much and as effectively as they did last year, each runner could find themselves as values come draft day.