Teams are getting ready to open training camps. Soon they’ll be playing their practice games. And as we work through this process in August, it’s important to remember that it’s not 2015 anymore. There will be changes – and real changes, not just incremental shifts.

Look at running backs, for example. Of the top-10 running backs of the last 10 years, almost half of those guys weren’t in the top 20 the previous year – 43 of those 100. Over a third of those running backs weren’t even in the top 30.

For this chart, I'm showing the player and the year he ranked in the top 10 (among backs). The numbers -- rank, yards and touchdowns -- show what he did in his previous season.

TOP-10 BACKS COMING FROM OUTSIDE THE TOP 20
YearPlayerRnkRecRunTotTD
2006Frank Gore, S.F.331316087393
2006Deuce McAllister, N.O.421173354523
2006Maurice Jones-Drew, Jac.Rookie--------
2007Willis McGahee, Balt.241569901,1466
2007Clinton Portis, Wash.331705236937
2007Adrian Peterson, Minn.Rookie--------
2008Thomas Jones, NYJ212171,1191,3362
2008DeAngelo Williams, Car.281757178925
2008Michael Turner, S.D.59163163321
2008Steve Slaton, Hou.Rookie--------
2008Matt Forte, Chi.Rookie--------
2009Ryan Grant, G.B.221161,2031,3195
2009Ricky Williams, Mia.362196598785
2009Joseph Addai, Ind.372065447507
2009Ray Rice, Balt.512734547270
2010Michael Turner, Atl.213587190610
2010LeSean McCoy, Phil.353086379454
2010Darren McFadden, Oak.502453576021
2010Arian Foster, Hou.56932573503
2010Peyton Hillis, Clev.971954731
2011Michael Bush, Oak.261946558498
2011Ryan Mathews, S.D.291456788237
2011Marshawn Lynch, Sea.301457378826
2011Darren Sproles, N.O.395202677872
2012C.J. Spiller, Buff.312695618306
2012Jamaal Charles, K.C.95983921
2012Trent Richardson, Ind.Rookie--------
2012Alfred Morris, Wash.Rookie--------
2012Doug Martin, T.B.Rookie--------
2013DeMarco Murray, Dall.242516639144
2013Knowshon Moreno, Den.311675256924
2013Eddie Lacy, G.B.Rookie--------
2014Lamar Miller, Mia.341707098792
2014Arian Foster, Hou.401835427252
2014Justin Forsett, Balt.7482311130
2014Jeremy Hill, Cin.Rookie--------
2015Latavius Murray, Oak.401434245672
2015Doug Martin, T.B.41644945582
2015Devonta Freeman, Atl.472252484732
2015DeAngelo Williams, Pitt.62442192630
2015Adrian Peterson, Minn.691875930
2015David Johnson, Ariz.Rookie--------
2015Todd Gurley, St.L.Rookie--------

Breaking it down, 11 of those 43 running backs were rookies. Only 9 of those running backs were guys who went from at least ranking in the top 30. So 23 of running backs (almost a quarter of all top-10 running backs) were players who played but didn’t even rank in the top 30 the previous season.

Bottom line: stuff changes a lot.

So when organizing your board, it’s not good enough to just kind of poke the guys around a little. That is, when you’re watching somebody like Duke Johnson Jr. or Carlos Hyde and you feel like they’re going to be a breakout back, it’s not good enough to say, “This guy ranked 30th among running backs last year; I’m going to move him up to 25th.”

More aggressiveness is needed. You’ve got to take a stand on some of the players, even while many around you see things playing out different. Much of that noise is created by people who don’t look at it carefully enough and are falling into the trap of thinking that 2016 should be pretty similar to 2015.

—Ian Allan