I think there’s a tendency to overrate rookie running backs selected in the middle rounds. A team drafts a guy like Isaiah Spiller, Rachaad White or Zamir White, and many tend to kind of assume those guys will be the backup running back – an injury away from relevance.

Then the team start playing, and those plans can quickly be forgotten. NFL offenses are complex (particularly in regards to the passing game) making it hard for running backs to contribute immediately. And when a player lasts until the middle rounds, that means he’s got some flaws anyway.

I will focus here on the fourth round, since that’s where Spiller was chosen. He’s the guy I started looking at initially when I started this project. The Chargers have drafted a couple other running backs in recent years, and I think it’s premature to assume Spiller will beat them out. Joshua Kelley, after all, also was a fourth-round pick, and he’s got the advantage of having been practicing in this offense the last two years. And Los Angeles picked Larry Rountree in the sixth round last year.

The Chargers in theory could also re-sign Justin Jackson. He was their 2nd-best running back at the end of last season.

It’s early, but in general I think Spiller at this point is about a 50-50 bet to be the No. 2 back for the Chargers this year. And I think it’s about the same situation in Tampa Bay with Rachaad White (who was picked in the late third rather than fourth round).

In general, this line of thinking is supported by how things have played out for other fourth-round running backs. Of the last 75 chosen in that round, 30 were one of the top 2 backs on their own team in their first season.

So I will slot these guys conservatively for now. If somebody started peeling off impressive runs in the preseason, that will change things.

Only 14 of those 75, by the way, finished with top-40 PPR numbers in their first season (and I’ve got them tagged with black dots).

2002Najeh Davenport, G.B.18453237128.788
2002Travis Stephens, T.B.06601.6150
2003• Domanick Williams, Hou.1,0313511,3828233.214
2003• Onterrio Smith, Min.5791297085117.838
2003LaBrandon Toefield, Jac.212105317365.363
2003Justin Griffith, Atl.168122290262.071
2003Quentin Griffin, Den.34561406048.674
2003Lee Suggs, Cle.2890289242.981
2003Jeremi Johnson, Cin.4182123239.382
2003Artose Pinner, Det.9940139018.9108
2004Mewelde Moore, Min.379238617088.745
2004Cedric Cobbs, N.E.5005005.0153
2005• Marion Barber, Dall.5381156535113.339
2005Alvin Pearman, Jac.149240389176.956
2005Brandon Jacobs, NYG99099751.972
2005Ciatrick Fason, Min.62062430.289
2005Darren Sproles, S.D.50106009.0127
2005Manuel White, Was.0000.0---
2006• Leon Washington, NYJ6502709204141.035
2006P.J. Daniels, Balt.0000.0---
2007Antonio Pittman, St.L.13915154018.4105
2007Dwayne Wright, Buff.9417111014.1118
2007Michael Bush, Oak.0000.0---
2008Tashard Choice, Dall.472185657298.753
2008Michael Bush, Oak.421162583395.755
2009Mike Goodson, Car.49156408.4133
2009Gartrell Johnson, NYG4304304.3145
2009Andre Brown, NYG0000.0---
2010Joe McKnight, NYJ18920209023.990
2011• Roy Helu, Was.6403791,0193168.925
2011Kendall Hunter, S.F.473195668294.845
2011Delone Carter, Ind.37718395256.571
2011Jamie Harper, Ten.443276117.6109
2011Taiwan Jones, Oak.732598011.8120
2011Bilal Powell, NYJ2172803.8145
2012Robert Turbin, Sea.354181535072.557
2012Lamar Miller, Mia.25045295141.582
2013Johnathan Franklin, G.B.10730137123.7104
2013Marcus Lattimore, S.F.0000.0---
2014• Andre Williams, NYG7211308517145.127
2014Devonta Freeman, Atl.248225473289.349
2014Lorenzo Taliaferro, Balt.292114406472.665
2014James White, N.E.382361011.1128
2014DeAnthony Thomas, K.C.00066.0120
2014KaDeem Carey, Chi.0000.0---
2015• Javorius Allen, Balt.5143538673149.729
2015• Jeremy Langford, Chi.5372798167147.630
2015Mike Davis, S.F.583896016.6118
2016• Devontae Booker, Den.6122658775148.729
2016Kenneth Dixon, Balt.3821625443102.447
2016Tyler Ervin, Hou.3182105.1140
2017• Tarik Cohen, Chi.3703537234154.428
2017• Jamaal Williams, G.B.5562628186142.834
2017Samaje Perine, Was.6031827852112.543
2017Wayne Gallman, NYG4761936691106.946
2017Marlon Mack, Ind.3582255834103.348
2017Joe Williams, S.F.0000.0---
2017Donnel Pumphrey, Phil.0000.0---
2018• Nyheim Hines, Ind.3144257394160.928
2018Ito Smith, Atl.315152467497.750
2018Chase Edmonds, Ariz.208103311263.172
2018Kalen Ballage, Mia.19156247139.786
2018Mark Walton, Cin.344175012.5109
2019Tony Pollard, Dall.455107562391.253
2019Benny Snell, Pitt.42623449259.967
2019Justice Hill, Balt.22570295249.577
2019Bryce Love, Was.0000.0---
2020Joshua Kelley, LAC354148502285.258
2020DeeJay Dallas, Sea.108111219356.973
2020Anthony McFarland, Pitt.11354167022.7102
2020LaMical Perine, NYJ0000.0---
2021• Michael Carter, NYJ6393259644156.429
2021• Chuba Hubbard, Car.6121747866139.636
2021Rhamondre Stevenson, N.E.6061237295116.947
2021Kene Nwangwu, Min.61970223.0105
2022Isaiah Spiller, LAC??????
2022Pierre Strong, N.E.??????
2022Hassan Haskins, Ten.??????
2022Zamir White, L.V.??????
2022Dameon Pierce, Hou.??????

—Ian Allan