It can be tricky to pin down exactly what a “starting” running back is in the NFL these days with committee backfields so prominent, so this list was limited to running backs with at least 150 rush attempts on the season. Sure, a player like (spoiler alert) Devontae Booker only became a starter due to injury, but the carry count is really all we have to work with as a jumping off point.

In addition, the running back position is by nature difficult to measure in terms of what a good or bad performance is. A player’s performance relies on any number of variables on any given play -- offensive line play, scheme and opposing defensive strategy are just a few. And when it comes to efficiency metrics like yards per carry, one big run can really throw off the needle.

That’s why we'll use numberFire’s Rushing Success Rate metric to determine who were the worst starting running backs in the NFL in 2016.

Success Rate is the percentage of total carries that resulted in a positive gain in Net Expected Points (NEP). NEP is the metric we use to measure the efficiency of both teams and players. There's a big difference between a two-yard rush on 3rd and 1 and that same two-yard rush on 3rd and 3, and NEP helps quantify those differences by showing the expected points added on each carry. You can find out more about NEP in our glossary.

Let’s get into it.