England had just been beaten by Sri Lanka in the second one-day international at Headingley and coach Brendon McCullum was speaking to his players in the dressing room.

"The game is slightly different now," he said. "The ball is playing a massive part."

The difference McCullum referenced is reverse swing - the way an older ball moves in the air in the opposite direction to convention.

The playing conditions in ODIs were changed in July 2025, allowing captains to choose after 34 overs which of the two white balls used at either end they would like to use to complete the rest of the innings.

With the chosen ball now able to get older and scruffier, the result has brought a reverse swing renaissance, something which is already having an impact on the format and poses intriguing possibilities for the future less than 12 months out from the next World Cup.

What has changed?

When Sam Curran bowled England to victory with four wickets at the death in the third ODI against India at Lord's in July, he found more than twice as much swing with the old white ball across his final spell than he did at the start of the innings.

A year earlier, Saqib Mahmood found less than half as much swing in an ODI at Cardiff against West Indies at the death compared to the start.

Those are two random examples. Different days, different players, different situations.

But it is reflected worldwide.

The change to using one ball for the last 16 overs was made to help bowlers, and it is having the desired effect.

Half of full deliveries from pace bowlers in the final 10 overs have swung more than one degree since the rule change - a jump from 35% compared to the 18 months prior.

As a result, the economy rates of pace bowlers in the final five overs have dropped from 8.40 runs per over in the period before the change to 7.95 - a small but not insignificant decline.

Pacers' bowling averages have dropped from 19.2 runs per wicket to 18.3 too.

The verdict? Hitting out at the death is not as easy as it once was.

England leading the way

As has always been the case when reverse swing is in play, pacers are bowling fuller and utilising more inswing now the ball is reversing.

Sri Lanka were particularly effective with this against England in the Headingley ODI last month, bowling 69% of deliveries six metres from the stumps or fuller. It helped them close out a 16-run win.

Despite that, England have, statistically at least, benefited most from the rule change, though it should be noted they have taken a significant step forward with their ODI cricket this year. Their numbers may have improved with or without the change.

Their bowling average (from 36.76 to 20.91) and economy rates (from 9.78 to 7.53) at the death have plummeted since July 2025, while their batting run-rate has actually improved (from 8.07 to 9.16).

After defeat in Leeds, McCullum asked his players to "think" about what the changes may mean for their own plans, suggesting tactical switches may follow.

Three days later at The Oval, England progressed from 104-2 to 214-2 in the 10 overs prior to the Sri Lankans picking their preferred ball.

What about the rest of the world?

Australia, New Zealand, West Indies, South Africa, Bangladesh, Pakistan and Afghanistan have all scored slower during the death overs since the rule change.

West Indies' death run-rate has dropped by 2.39 runs per over in that time.

As for individual bowlers around the world, Windies quick Alzarri Joseph and South Africa's Lungi Ngidi have benefited from massive jumps in the amount of swing they have been able to find at the death.

Joseph's average amount of swing has increased by 84%, leading to his bowling average dropping from 24.1 to 17.4.

Similarly, Ngidi's bowling average has dropped to 13 and his economy has fallen from 9.34 to six after a 63.3% increase in swing.

Others to see their movement jump include New Zealand's Nathan Smith, Pakistan's Naseem Shah and Bangladesh's Mustafizur - each with varying results.

Shaheen Afridi, Pakistan's captain in this tri-series, is one of the world's best at finding swing at the death (an average of 1.3 degrees since the rule change), although he was swinging it plenty before the change too (1.2).

Shaheen and Naseem in tandem against England on Tuesday could be a fascinating sight.

Jofra Archer is the England bowler finding the most movement late on, with an average degree of 0.97 - an increase of 37%.

What impact might it have on the World Cup?

Reverse swing is not impacting ODIs everywhere in the world - not yet, at least.

The change has been most significant in England, where the ball is swinging 63% more at the death.

There has been a 33% jump in Bangladesh, with matches held in Sri Lanka, Bangladesh and Pakistan - relevant for the next two weeks - also featuring significantly more late movement than before.

The increase has been less significant in Australia, where England travel next, however, and in South Africa where the majority of next year's World Cup will be held.

There have only been three ODIs played in South Africa since the rule change, making predictions for next autumn difficult.

While the change has not taken effect there, South African ODIs already have some of the higher levels of movement late in an innings but, at the same time, teams have scored at 7.35 runs per over there in recent years - again on the higher side.

If a spike in reverse swing does come, teams may have to get their scoring done earlier than previously.