Regression, How would you do it?

[SwagSloth]

Different regressions per position would be more realistic, but it would also require longer positions to start with lower stats and/or gain TPE slower. If we're really aiming for realism, though, speed/agility should regress faster than other attributes. Positions that don't rely on speed/agility like Oline, Dline, QB, or K tend to last longer in the NFL because players slow down as they age. Granted, some QBs rely on speed, but they either retire earlier or change their style as they age.