One of the things that I’ve argued in the past as it relates to the receiving positions is that teams are better off just focusing on TD catchers. Defenses are actually configured to give up yards as they ask you to string together long drives, while they hope those drives are just fragile enough to keep you from putting points on the board. Bill Belichick’s defenses (when he was still a defensive guru) were famous for not giving a shit where they ended up ranked in yards allowed, while they would finish in the top 5 in scoring defense each year.
So when teams select receivers, and do it with an eye for players that can roll up yards (perhaps at the expense of finding TD catchers), they might be feeding right into the defense’s game plan.
Related to this theory, I was interested in which is a more unique skill, the ability to compile receiving yards, or the ability to compile receiving touchdowns. If catching touchdowns is the more unique skill then when a team’s top TD catcher is out of the lineup I would expect a team to have problems replacing the player’s TD output. That is, compared to how they would fare in yards when their yardage leader is out of the lineup. I would also expect the same to be true of the first downs. To test these theories I ran some numbers using games from the past 14 years.
It turns out that touchdowns are probably harder to replace than yards or first downs. Here’s a graph that shows the percent of the applicable stat that a team compiled when their season leader in that stat was out of the lineup:
This is based on over 200 games for each stat where a team’s leading player in that category is out of the lineup. You can see that yards and first downs are replaced at a 90% rate, while TDs are only replaced at about a 70% rate.
You might call this the Harry Douglas Rule. In 2013 when the Falcons lost two of the best receivers in the league, they still had a 1,000 yard receiver. In fact Harry Douglas’ yardage output wasn’t that much lower than Julio Jones’ yardage output from the 2012 season. But Douglas only had 2 TDs in 2013, while Jones had 10 TDs in 2012. It was easy for the Falcons to replace yardage, while it was tougher to replace touchdowns. This is an anecdotal illustration of the idea, rather than a literal explanation of my methodology. In my work I actually looked at same season results where a top producer was out of the lineup.
This information makes yards something that just sort of happens in football games. Certainly there will be instances where teams have trouble even compiling yardage, but to some degree yards can be transferred from player to player in an offense.
This is actionable information for NFL and fake teams. NFL teams should probably spend less time looking for chain movers as that skill seems to be fairly replaceable. Instead they should focus on finding players that can put points on the board.
For fake teams this has utility as it relates to daily games. When you see a team missing a yardage compiler, you’ll have some confidence that the QB can probably find other receivers to rack up close to the same yardage totals. But when the TD catcher is out of the lineup it’s probably more troublesome. Note that in some cases the top yardage producer and TD producer will be the same player, so that’s worth thinking about as well.