Explained: The how, where and what of replacement balls in Test cricket

A common theme during the England-India Test series has been the frequently replaced balls because the original ones are losing shape. Ever wondered where the replacement balls come from, how they are sorted and selected? Here is all you need to know.

Two or three days before the Test, the host association provides used balls from first-class matches played in its venue. If it is Old Trafford, for example, Lancashire provides these balls to the fourth umpire, New South Wales for SCG, Mumbai Cricket Association for Wankhede, and so on.

The fourth umpire then inspects the balls putting them through the gauge. If it goes through one and not through the other, it is considered eligible to go into the "ball library", which is the box you see coming out when a ball is changed during a Test match. Any ball that goes through both the rings is ineligible to start playing with in the first place. So if it goes through both, it is too small to be in use. If it goes through neither, it is too big. If it goes through one and not the other, it is the right size. The number of these potential replacements depends on venues. Tests in India, England and Australia generally tend to have about 20 replacement balls, but in some countries the number can be as low as 12.

If the fourth umpire sees an issue with most of the balls or doesn't see enough eligible balls, they bring it up with the rest of the officiating team - on-field umpires, third umpire and match referee - and then they collectively ask the association to provide for more. The same process is followed for new balls. Every new ball is put through the rings before the Test.

The endeavour is to have the largest possible range available from semi-new to old, but they are not batched according to age. A ball that has been used for 60 overs on a lush outfield could well be a replacement for one used in a Test on a drier outfield for just 30 overs.

No, it is not possible to bring an exact like-for-like replacement. The best they can hope to do is get a replacement ball that is nearest to the original ball in wear and tear. It could be older or it could be newer.

This is why the umpires are reluctant to change the ball unless it has gone completely out of shape. To maintain the integrity of the competition, the rule of the thumb is to change it only when there is no other way to continue with the existing ball. The teams of course want a ball that suits them; any change is liable to leave one of them unsatisfied.

Also remember that the laws doesn't provide for a ball change for softness. The ball is changed if there is clear damage, wetness or loss of shape. Even with the shape, nowhere do the laws mention the ball has to be round. The only shape criterion for a ball change is that if it goes through neither or both of the rings on the gauge. If it goes through one and not through the other, and if its seam is in place and the ball is dry, you have no option but to continue with it no matter how soft it feels.

No, the match officials have to act on their feet sometimes. If they feel they are running out of replacement balls rapidly, they can ask the teams to provide used balls from their nets. They are run through the same tests before they are sent into the ball library.

Another source is match balls from earlier in the series. If an innings in an earlier Test in the series has lasted 45 overs, that ball can sent into the library provided it passes the quality checks and no bowler wants to keep it as a souvenir for a five-for.

There have also been cases where the match balls have gone out of shape rapidly and the match referee has had to send for more from the neighbouring county or state association.

Yes, but nobody knows which ball is which. There is no marking done on the ball, and once the balls go into the library it is near impossible to tell them apart.

Yes they can, but they do it only when they suspect ball tampering or if they ball is damaged to the extent that just tidying up with a pair of scissors is not enough.

The thing with ball tampering is that since it is an accusation of cheating, it needs visual evidence. The umpires avoid making such explicit charges, but do quietly change the ball if they see something is off.

Umpire-led changes of the ball are, however, rare. The ball goes to them for a check at every dismissal, during drinks break, if it has hit an LED board or been in the crowd, and during longer intervals. They don't check it between overs or during overs.

So, the ball change on the second morning at Lord's - when the ball was clearly out of shape but was also doing a lot for India - would not have eventuated had India not asked for it. As it turned out, the replacement ball did nothing for them and went out of shape in eight overs.

Test cricket uses three brands of balls: SG in India, Dukes in England and the West Indies, and Kookaburra elsewhere. Balls losing shape is not limited to any particular brand.

There was a time in the late 2010s when SG used to lose shape often, and the Indian players used to bring it to notice despite being sponsored by SG. Kookaburra has often being criticised for the least prominent seam of all three, but its manufacturing process has reinforced the seam in recent years. Dukes just happens to be in the eye of the storm now with frequent complaints from both sides. Even in the concurrent series in the West Indies, especially in the first Test, the players didn't quite like the ball.

However, a lot of it is also gamesmanship. You usually see complaints only when the wickets are not falling. On the last day of Lord's, when it was in England's interest to bowl with a softer ball to deny Ravindra Jadeja striking opportunities, the shape of the ball was never brought into question. Often, bowling sides just take a punt when nothing is happening for them in the hope that the library doesn't have a ball that will be any worse than the one than they have in hand.

Dukes has an advantage over the others when it comes to being replaced. The ball has a stamp, the equivalent of a batch number, to identify the year of manufacture. So it is not possible to be playing in 2025 with a Dukes ball that was, say, last used in 2023 or was part of another production batch. SG and Kookaburra don't have such identification markers.