Why a fourth-and-15 play isn’t a gimme — even for Patrick Mahomes

Will the NFL’s proposed rule change — which would give teams the option to replace an onside kick with a normal fourth-and-15 play from their own 25-yard line — give a substantial advantage to the Kansas City Chiefs?

Probably not.

And would the rule change — as Chiefs head coach Andy Reid hinted on Friday — substantially affect the integrity of the game?

Again... probably not. In fact, the rule change would likely restore the integrity of the game.

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On Friday, I wrote about this potential rule change — which the NFL will be voting upon during their (virtual) league meeting this Thursday. Twice in a game, a team could inform the referee that instead of kicking off, they’d rather try a normal fourth-and-15 play from their own 25-yard line. If they make the first down, they retain possession. Otherwise, the opponent gets the ball where the play ends.

This rule — which was proposed by the Philadelphia Eagles — is similar to one the Denver Broncos proposed a year ago. The Broncos’ version had more limitations. The fourth-and-15 option could only be used following a score — and even then, just once in the fourth quarter. It also started 10 yards farther upfield — that is, from the 35-yard line.

Despite being passed 7-1 by the league’s competition committee, the owners voted down the Broncos’ idea a year ago. But as you’ll recall, that was when most of the attention was focused on the proposed change that would allow coaches to challenge pass interference. That rule won’t survive beyond the 2019 season; after an overwhelming majority of challenges were upheld in 2019, the league isn’t even considering a vote to make it permanent. But this time around — without the distraction — the Eagles’ proposed rule may have a better chance of being ratified.

Why? Because it should be.

Photo by Maddie Meyer/Getty Images

“I’ve got kind of mixed thoughts on it,” said Andy Reid on Friday. “Being an old guy, I’d probably stick with the integrity of the game as it sits right now — but I could also see where the other part could be exciting, too.”

As a fellow old guy, I understand where Reid is coming from. Just like him, I’d be opposed to a rule that would eliminate kickoffs — an idea that was gaining steam before the league modified its kickoff rules in 2018. Once that happened, one of the game’s most dangerous plays was made much safer — and two years later, nobody is talking about eliminating kickoffs any longer.

But the kickoff rule change did have the effect of making an onside kick virtually impossible to execute — and that violated the integrity of the game.

Unlike some other rules, onside kicks weren’t added to the professional game during the 1970s or 1980s in order to make them higher-scoring and more exciting. Instead, they’ve always been part of the game. They’ve been a safety value that’s allowed teams to attempt comebacks when trailing their opponents — and occasionally, as an offensive weapon to catch an opponent off guard.

During the last 10 seasons before the kickoff rules were changed, onside kicks attempted by trailing teams were successful 23% of the time. In other words, they worked often enough to justify the risk of trying them when teams were desperate for an extra score — but not so often that opposing teams’ leads could easily be erased; most of the time, leading teams ended up with an even better chance to win.

But since the kickoff rules were changed, that’s changed dramatically. During the last two seasons, trailing teams have successfully executed onside kicks less than 10% of the time — making them so unlikely to be successful that coaches will simply stop trying them.

And that would be a shame.

One of the things that has made the NFL successful is that fans know games aren’t really over until they’re over — and the onside kick is one of the things that has made that possible. Without a realistic opportunity for teams to get an extra chance at a score, teams with a two and three-score leads going into the fourth quarter will tend to cruise to victories more often.

Some have suggested that the Eagles’ proposed rule will make it too easy for a trailing team to retain possession. The evidence, however, says otherwise. Over the last 10 seasons, third and fourth-down plays with 15 to go have been successful just 16% of the time — which is even less often than trailing teams were previously able to recover onside kicks. And if the conversion fails, the opponent will get the ball no further than 39 yards from the opposing goal line — which makes a field-goal attempt pretty likely. To be sure, those are still pretty long odds — but they’re good enough for teams with nothing to lose to give them a shot.

So this rule — rather than hurting the integrity of the game — is more likely to help restore the conditions in which it existed during its first 100 years.

But what if your quarterback is Patrick Mahomes?

When I wrote about this rule change on Friday, I included a chart showing that on third and fourth-down plays of 18 yards or more, Mahomes has a cumulative Expected Points Added (EPA) that is head and shoulders above any other quarterback over the last 10 seasons.

That probably gave the wrong impression about Mahomes’ ability to convert a fourth-and-15 play — because when our Ethan Douglas created that chart last December, he had chosen that 18-yard threshold for a specific reason displayed in another chart from the same article.

Ethan had noticed that on even longer goal-to-go situations, Mahomes’ conversion rate had been much higher than rest of the league. In fact, in 15 such plays, Mahomes had been simply spectacular, converting 47% of the time and throwing three touchdown passes for a perfect passer rating of 158.3 — which accounts for the huge accumulated EPA. But as this chart shows, when at third or fourth down with just 15 yards to go, Mahomes had been right at the league average.

In a fourth-and-15 play to replace a kickoff, Mahomes is unlikely to continue that blistering 47% pace — but even if he could, it probably wouldn’t lead the Chiefs to consider using their two opportunities in the first quarter to run up a lead. More than half of the time, it would be more likely to lead to a field goal by their opponent. At the beginning of a game, that’s not a gamble Andy Reid — or even a more aggressive coach — is likely to take.

But if the Chiefs have just scored to narrow a deficit to 28-21 with three minutes to go, Reid will take that chance every time.

In Super Bowl LIV, 2-3 Jet Chip Wasp taught us that.