Here's a good article from SportingNews which uses hard data to show why. Like kickers and defenses, rarely do last year's IDP leaders repeat the following year.
Why can't you just pick defensive players based off last year's stats? Consider:
- Of the 12 defensive linemen with at least 10 sacks last year, only Aaron Kampman and Jason Taylor reached double digits the previous season.
- Of the 13 linebackers with at least 120 total tackles last year, five had done it the previous season. Another three were rookies.
- Of the eight DBs with at least 93 total tackles, only Sean Jones and Sammy Knight had more than 70 in '06.
The top three in sacks last year -- Jared Allen (15.5), Patrick Kerney (14.5) and Mario Williams (14) -- had a combined 16.5 sacks in '06. In fact, Allen led the league despite being suspended for two games. His move to Minnesota could affect his production, however. Again, don't be in a hurry to get your No. 1.
Don't chase interceptions. Of the seven defensive backs with at least six interceptions last year, only Ed Reed and Asante Samuel had more than three the previous season.