There are two main reasons why you should wait to draft a defense. The good news is that the fantasy football community is trending in the right direction. The bad news is that defenses are still overvalued by way too many drafters. For this article, assume the league drafts 16 rounds and has 12 teams.
The first reason that you should wait to draft a defense is because defenses are unpredictable from year-to-year in the fantasy world. More often than not, the top scoring defense is undrafted from that current year. Last year, the top scoring fantasy defense was the San Francisco 49ers (undrafted in 2011) with 177 fantasy points. The Chicago Bears, Baltimore Ravens and Seattle Seahawks were the next three best fantasy defenses who were drafted seventh, sixth, and undrafted respectively.
The second reason why you should wait is because the difference between points scored by a defense is negligible. The Chicago Bears (second-best defense) only averaged two more fantasy points per week than the New York Jets and Cincinnati Bengals (11th and 12th best defense). Even if you can’t predict who will be one of the top defenses, you shouldn’t waste a pick in the ninth or 10th round, because, in the long run, the defense’s contribution to fantasy points is insignificant when compared to one another.
For example, the first two defenses drafted last year (Pittsburgh Steelers and Green Bay Packers) were selected in the eighth round! Neither defense finished in the Top 5, and the Steelers were three fantasy points away from being the 12th-best defense and were barely startable. Instead of drafting a defense in the eighth round, you could have selected Jordy Nelson, Steve Smith, Eli Manning, A.J. Green or Rob Gronkowski! I didn’t expect any of these guys to have a season like they did, but I still would have guaranteed that they would have been a better pick than a defense.
Ten years ago, there were six defenses drafted in or before the 10th round, with the Tampa Bay Buccaneers being drafted in the sixth round. In 2006, the trend started to generally head in the right direction. More defenses were being selected later, but the first few were still off the board way too early. In 2009, it became better still with the first defense being drafted in the eighth round and even less drafted before the 15th round. And finally, as far as drafts are showing so far, the first defense (San Francisco 49ers) is being drafted in the 10th round this year. The better news is that the next defense won’t be off the board until the 14th round!
The bottom line is that a defense (and a kicker for that matter) should not be drafted before the 15th round, period. Take your chances on a rookie or draft the handcuff to your starting running back. There will always be a defense to scoop up at the end or in free agency, and half the time it will outperform your opponent’s defense anyway.