England had fallen to Sri Lanka in the second one-day international at Headingley when coach Brendon McCullum addressed his squad in the dressing room.

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

The shift McCullum highlighted involves reverse swing, where an older ball curves in the air contrary to standard expectations.

ODI playing conditions were updated in July 2025 to let captains select after 34 overs which of the two white balls in use they preferred for the remainder of the innings.

Because the selected ball can now age and roughen further, reverse swing has returned strongly. This development already influences the format and raises interesting questions less than a year before the next World Cup.

England leading the way

When Sam Curran took four wickets to seal victory for England in the third ODI against India at Lord's in July, he generated more than double the swing with the older white ball in his final spell than he had earlier in the innings.

By contrast, a year before that Saqib Mahmood produced less than half the swing at the death in an ODI at Cardiff versus West Indies compared with the opening overs.

These instances are isolated yet the pattern appears globally.

The decision to employ one ball for the final 16 overs aimed to assist bowlers and is delivering results.

Half of full deliveries from pace bowlers in the last 10 overs have swung more than one degree since the rule change, rising from 35 percent in the prior 18 months.

Consequently, pace bowlers' economy rates in the final five overs have fallen from 8.40 runs per over before the change to 7.95, a modest yet meaningful improvement.

Pacers' bowling averages have also declined from 19.2 runs per wicket to 18.3.

The outcome is that aggressive batting at the death has become less straightforward.

As reverse swing features more often, pacers are pitching fuller and seeking greater inswing.

Sri Lanka applied this approach effectively against England at Headingley last month, sending 69 percent of deliveries six metres or closer to the stumps and securing a 16-run victory.

Even so, England have recorded the clearest statistical gains from the rule change, although their overall ODI progress this year must be acknowledged. Their figures might have risen regardless.

Since July 2025 their death bowling average has dropped from 36.76 to 20.91 and economy rate from 9.78 to 7.53, while their batting run-rate has risen from 8.07 to 9.16.

After the Leeds defeat McCullum urged his players to consider how the changes might affect their strategies, hinting at possible tactical adjustments.

Three days later at The Oval, England advanced from 104-2 to 214-2 in the 10 overs before Sri Lanka chose their preferred ball.

What about the rest of the world?

Australia, New Zealand, West Indies, South Africa, Bangladesh, Pakistan and Afghanistan have all posted slower scoring rates in the death overs since the rule change.

West Indies' death run-rate has fallen by 2.39 runs per over during this period.

Among individual bowlers, West Indies seamer Alzarri Joseph and South Africa's Lungi Ngidi have recorded large increases in swing at the death.

Joseph's average swing has risen 84 percent, cutting his bowling average from 24.1 to 17.4.

Ngidi's bowling average has fallen to 13 and his economy rate from 9.34 to six following a 63.3 percent rise in swing.

Other bowlers showing increased movement include New Zealand's Nathan Smith, Pakistan's Naseem Shah and Bangladesh's Mustafizur, each with differing outcomes.

Shaheen Afridi, Pakistan's captain in the current tri-series, ranks among the world's best at generating swing at the death, averaging 1.3 degrees since the rule change, though he already achieved 1.2 degrees beforehand.

Shaheen and Naseem operating together against England on Tuesday could prove compelling.

Jofra Archer leads England bowlers in late movement, averaging 0.97 degrees, a 37 percent increase.

What impact might it have on the World Cup?

Reverse swing has not affected ODIs uniformly across all venues so far.

The change has been most pronounced in England, where the ball swings 63 percent more at the death.

Bangladesh has seen a 33 percent rise, and matches in Sri Lanka, Bangladesh and Pakistan, relevant for the coming fortnight, also feature notably more late movement.

The increase has been smaller in Australia, England's next destination, and in South Africa, host of most matches at next year's World Cup.

Only three ODIs have occurred in South Africa since the rule change, complicating forecasts for next autumn.

Although the change has yet to register strongly there, South African ODIs already produce relatively high late-innings movement, yet teams have averaged 7.35 runs per over in recent years, also above average.

Should reverse swing increase, sides may need to complete their scoring earlier than before.

Statistics correct prior to ODI tri-series between Pakistan, Sri Lanka and England.