From Knile Davis to Tre Mason, from Justin Forsett to Denard Robinson, we’ve already seen a number of backup running backs step into the starting lineup and find success. This isn’t a new trend. Every year, a number of running backs go down with an injury, and every year, their backups produce at a high enough level that it seems as though there isn’t any drop-off.
This shouldn’t be particularly surprising, for two reasons. First, we know that running back production is extremely reliant on a heavy workload such that predicting fantasy points at the position is almost exclusively about accurately projecting touches.
Second, because running back production comes independently of actual running back talent, it’s really difficult to assess the position. There are certain predictors of running back success that seem to work, such as straight-line speed, but running backs are difficult to analyze because they’re so reliant on their teammates, namely the offensive linemen.
We see evidence of these difficulties in the NFL draft, where running backs drafted in the third round or later since 2000 have actually been more efficient on a per-touch basis than those selected in the first two rounds. Simply put, many teams kind of stink at picking running backs. Part of it is probably their own fault, but a major factor is the difficulty involved with separating a running back’s talent from the ability of his offensive line.
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Backup RB Efficiency
Still, it’s not like we’d expect backups as a whole to be better than starters, so what kind of decrease in efficiency can we expect when a backup works his way into the starting lineup? Below, I charted the YPC for RB1s versus RB2s when each is the starting running back. These numbers don’t include backup running back stats when they are actual backups—just when they enter the starting lineup because of an injury.
From 2009 to 2013, starting running backs averaged 4.24 YPC, while backups averaged 4.17 YPC. To give you an idea of how small that difference is, consider that over the course of 100 carries—maybe six or so games for the typical starting running back—the difference amounts to seven yards. That’s just over one yard per game. So yeah, it’s basically meaningless.
Because of this, we see very mediocre running backs finish as high as RB1s in fantasy football quite a bit. Knowshon Moreno was the No. 4 overall running back in 2013 and I’d argue that there are dozens of backups in the NFL who are better than him. If you let me play with Peyton Manning and I see a heavy enough workload, I don’t see any reason why I personally couldn’t rush for 2,500 yards in the NFL. Easily.
Backup RB Bulk Stats
Once a backup becomes a starter, there’s typically a value opportunity to be exploited. In season-long leagues, I think it makes sense to buy low on newly anointed starting running backs, assuming the original starter is out for an extended period of time.
You might argue that you’re not buying low on someone whose stock just soared, but I disagree. If you can pay a ‘B’ price for an ‘A‘ fantasy player, it doesn’t matter if he was a ‘D’ player yesterday. If he’s an ‘A’ running back now and you think he’ll continue to be that moving forward, you’re buying low.
Typically, most owners are going to factor in some uncertainty with backups who haven’t been starters, reducing their cost. There’s really not much uncertainty, though; running back is such a plug-and-play position, and outside of the few truly elite talents like Matt Forte, the position is really commoditized. Pick a running back, any running back, and he can probably be productive if given opportunities.
That’s evident when you consider how RB2s have performed in terms of fantasy points when they take the lead.
Despite rushing for slightly fewer YPC, backups have scored more fantasy points per game than the original starters since 2009. Are the backups really better? No, but 1) it’s close, 2) teams aren’t going to just stop running the ball, and 3) a lot of backups are groomed to be pass-catchers who specialize in third downs, which helps their fantasy value.
If you own a backup who has even a decent level of talent and he’s going to see the same workload that the starter did, don’t trade him (unless the starter is expected to be out like a week or something); normally, market value won’t approach actual value. If you don’t own such a player, consider trading for him.
In daily fantasy leagues, there’s no prettier sight than when a starting running back tears his ACL. Wait what!? Just kidding (but not at all). When a running back gets injured, his backup will normally be priced too low on the daily sites. That’s particularly true if the back gets injured during the week, because the site will have already priced the players, so the backup will normally be much too cheap. You can make a lot of money by targeting low-priced backups who start because the normal starter is a last-minute scratch, for example.
Emphasize the Same Traits
The numbers are obviously an average and you still need to consider every case individually. Though most of the time you don’t need to be scared off by backup running backs, you should still emphasize the same traits you want in any back: a heavy workload, first and foremost, followed by explosiveness (as measured by the 40-yard dash and broad jump) and pass-catching ability.
The first of those is ultimately the most important. Running back production is 90 percent about workload. Fantasy football strategies can get pretty complex at times, but it doesn’t get much simpler than “target running backs who are going to touch the ball a lot, dummy.”