The title says "best running back seasons," but I actually compiled a list of "all (qualifying) running back seasons" of the last 10 years. Why limit yourself, right? Anyway, we are measuring "best" by Football Outsiders' DYAR statistic. For those unfamiliar, it accounts for context in a way traditional stats do not. It considers down, distance, location on the field, and quality of opposing defense. It then compares the results to a theoretical replacement level. This allows efficiency to overcome a lack of volume and punishes a player for accruing a bunch of yardage just due to high volume.
The least surprising result of this is that LaDainian Tomlinson's record-setting 2006 season tops the list and it does so by a huge margin. It's also no shock that his 2007 season comes in second. What might surprise people is that Danny Woodhead takes two of the remaining top-five positions with his work in 2013 and 2015. Most of Woodhead's value comes from the fact that he is a tremendously effective receiver. His receiving DYAR alone in 2013 was worth more than any total output from any 'back not named LaDainian Tomlinson or Ryan Mathews.
Another guy that really stands out is Darren Sproles who achieved his place on the list in largely the same way Woodhead did. Sproles is the only player to appear three times in the top 10. Tomlinson, Mathews, and Woodhead all appear only twice, and Michael Turner gets on once.
Take a look at the whole list:
The bottom half of the list is mostly full backs and guys nobody wanted to see getting playing time. The bottom five, though, include down years from Tomlinson and Turner, and Gordon's rookie campaign. Hopefully, Gordon's future looks more like LT and Turner and less like Donald Brown and Jacob Hester.