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Drafting Individual Defensive Players

Most fantasy leagues involve only offensive players but drafting individual defensive players is becoming more common. We were recently invited to participate in Fantasy Football Indepth’s IDP Challenge so I decided to do a statistical analysis to find out when individual defensive players should be selected in these types of drafts.

The Average Draft Position Analysis Article compared the average draft position of players at each position with their end of year statistics. This statistical analysis is quite similar to that one but instead of looking at average draft position I will look at statistics from the previous season. It is not a perfect method but the situation does not change as much for defensive players from year to year so most people draft based on statistics from the previous year. I wanted to improve on that since as mentioned quite a bit in other articles, some statistics such as touchdowns are much harder to repeat than others. In the case of defensive players, a player such as Patrick Willis is much more likely to have over 150 tackle again than Antonio Cromartie is of having 10 interceptions again. The statistics used in IDP leagues are usually tackles, assists, sacks, safeties, interceptions, touchdowns, forced fumbles and fumbles recovered. In order to calculate which of those are easier to repeat, I looked at statistics from the past five years and imputed them in a program which gives a formula that best predicts how the player did in the following year. For example, to have the most accurate average prediction of a player’s tackles you take his previous year’s number, multiply it by 0.54 and add 23. This means that players who have 100 tackles will generally average 77 (0.54 x 100 + 23) in the following year. Here is a chart that shows the best formula to predict each of the statistics mentioned earlier:

We have projected the statistics for the top 300 defensive players based purely on these formulas and they are adjustable to your scoring system which you can download here. Please note that these statistics are not adjusted for games played so some players will be lower than they should be but it should give you a general idea of what you can expect from defensive players this year. Although the rankings can be interesting to look at the part that interests me the most is the difference in points between players. The scoring system used for Fantasy Football Indepth’s IDP Challenge is the following:

The starting lineup consists of two defensive linemen, two linebackers, two defensive backs and offensive players of course. There are twelve teams in the league so each week there will be a total of 72 defensive players starting, 24 at each position. The following chart shows the difference between the top player’s fantasy points projections and the 24th best’s projections at each position:

As you can see the biggest difference is between linebackers but if you take out Patrick Willis and Brian Urlacher, the difference drops to 14.4. This means that with this scoring system, other than Willis and Urlacher you should draft defensive linemen before linebackers and defensive backs. These differences are quite low however because as you can see in our Average Draft Position Analysis Article, the difference between the top wide receiver and the 36th receiver (since most leagues start three WRs) is about 125 fantasy points. It is about the same for running backs while for tight ends it’s around 100 and around 60 for quarterbacks. In other scoring systems these differences may be higher but in this case, defensive players are worth much less than players at every offensive position. The main reason to explain this is that teams will generally have four defensive linemen, three linebackers and four defensive backs on the field at the same time but they will only have one starting quarterback. Furthermore, some defensive player statistics such as touchdowns and interceptions are very hard to predict and vary a lot from year to year.

In conclusion, as shown by the statistics above, defensive players in IDP leagues are not as valuable as some may think. We will analyze individual players more within the next few days but it is very unlikely that we will draft any defensive players before the 11th round (after 2 QBs, 3 RBs, 4 WRs, 1 TE) and probably later depending on how the draft goes. We could be tempted by Patrick Willis earlier but he is likely to be gone by that time. Although the scoring system may be different in your league, it is quite obvious that defensive players do not have very much value and you should wait until much later in your drafts to select them.