The NFL has been working to reduce collisions for a decade and kickoffs have been a primary focus. Ten years ago, kickoffs were returned 79 percent of the time and last year that number fell to a low of 36 percent.
The drop was encouraged by two rule changes. In 2011, the kickoff was moved to the 35 yard line and that increased a kickers ability to reach the end zone.
In 2016, touch backs were moved from the 20 to 25 yard line reducing the incentive to run the ball out of the end zone. Notice in the chart above that the change actually resulted in fewer kicks reaching the end zone. This rule change spawned a new kicking skill which was to add loft to the kick and land it as close to the 1 yard line as possible. This turns out to be a good tactic.
The 2011 rule change also impacted the decisions to return the kick. This is likely because kickers are able to get more air under the ball and still reach the end zone, or they can simply kick the ball even deeper than before.
The above chart shows that the returns when the ball is kicked into end zone declined to just 19 percent last season. Amazingly, that number was at 74 percent in 2010.
Should one in five kickoffs into the end zone be returned? Or should everyone be taking a knee? Clearly coaches are giving returners some freedom to choose, but just how wise is a return given the new rules?
The below chart plotting kick returns since the 2012 season reveals that on average, if a ball is kicked into the end zone, it is a bad idea to run the ball out. While the return distance increases as the kickoffs go farther (and encourage returners with contracts on their mind to run it out) the average starting field position decreases, and is ultimately before the 25 yard line. Even kickoffs to the 1 yard line result in a starting field position before the 25, indicating perfecting that strategy is a useful skill.
Applying expected point models to the potential change in field position suggests that if no end zone kickoffs were returned there would be 60 more points per year in the league, a 0.5 percent increase over 2018 numbers.
But that doesn’t mean there should be no returns from the end zone, because risks are worth taking at the right time. In general we think of risk taking as good when the expected outcome is bad and there is no further downside to the bad outcome. If a team is expected to lose, and all losses count the same, then they should take risks that increase their chance of winning, even if the result is a loss by a wider margin. It’s the same logic and math that encourages coaches to pull goalies late in hockey games.
Using a football example, if a team is a ten point underdog on the road, perhaps they should run out all of the end zone kickoffs. They might lose by twelve instead, but they are almost as likely to close the gap. Falling further behind has no loss of value, but potentially closing the gap does have tangible value. The opposite holds true when a team is favored. Unless a team has a distinct advantage in the kicking game, there is little incentive to take incremental risk if they already expect to win the game.
The NFL does not appear to approach kickoff returns with this line of thinking. Looking at end zone kickoff returns by the state of the game reveals very little change.
Steelers fans might be encouraged that the team runs out of the end zone less frequently than their peers, even if they too don’t factor game state into the equation.
Over the last three seasons 22 percent of kickoffs into the end zone are returned, and that rate does not change significantly when looking at the score of the game. The team expected to win should run it back less frequently, only when they are confident they can average starting field position past the 25 yard line. The team more likely to lose should increase their returns substantially to increase the chance of big plays that reduce the score differential.
The net effect of these changes would increase the number of kickoffs, but that would probably be a short lived change. The NFL would likely respond with another rule change to keep those collisions to a minimum. For now a team looking to optimize their ability to win should take a strong look at their kickoff return decisions.