Since the World Cup, spinner Axar Patel has conceded 9.1 runs an over in 17 T20Is. His precision has slipped, with deliveries often missing their intended mark. "Kabhi kabhi yeh hota T20I mein," he said. India now faces a tough choice on whether to keep him in the team.

Since the World Cup the left-arm spinner has gone at 9.1 an over, bowling faster and slower than he wants to, and India must decide whether to stick or twist

An odd six or two doesn't bother Axar Patel. "Kabhi kabhi yeh hota T20I mein (This happens sometimes in T20Is). Even your best balls could be hit for six. You try not to repeat the same mistake and bounce back," he once told this newspaper. Had he brooded over the sixes struck off his bowling, he wouldn't have built the imposing career he has. Yet some sixes sting. Bowlers fall apart, begin to question themselves, and become unrecognisable.

It took just one violent swipe from Finn Allen for Axar to turn into a different man. Allen backed away a fraction from the stumps and bludgeoned the full ball outside off-stump over long-off. It was a staple Axar ball, one most batsmen would have nudged for a single. But he was a yard slower than he had thought, and Allen had adequate time to process his options. Axar blew his cheeks in anguish.

This is the crux of Axar's T20 smarts: landing the ball on the precise spot he wants, at the exact pace and angle he chooses. Behind his recent travails is the slow waning of the virtue that made him India's foremost white-ball spinner. Not every ball does what the bowler wants, but Axar's deliveries are disobeying him more often.

The margins are fine: a yard shorter, an inch fuller, the angle a trifle wider. For a bowler who has built his game around fine margins and subtleties, and not a stack of variations, even minor aberrations can be damning in the most punishing format of all for bowlers.

Since the World Cup, his numbers paint a disturbing picture. In 17 T20Is, he has conceded 9.1 runs an over, a substantial spike from his earlier economy rate of 7.7. Take out the Asian Games and the one-off Japan match, where his economy rate was 5.28, and his ability to strangle batsmen has diminished across conditions. England's batsmen scored at 11.14 an over against him in England; West Indies' at 12.21; Allen and company at 12.75. Some of the decks were horribly flat, but choking batsmen irrespective of conditions was his calling card.

The stats are not the cruellest portrait. It is that he can no longer produce what he habitually did. Take pace modulation. He was always on the quicker side, consistently in the 95-100 kmh band. But often he would reduce the speed without any discernible reduction in arm-speed. The change in speed is more discernible these days, especially when he tries to bowl faster than his normal range. At Hagley Oval he often stretched the speed gun to 102-103 kmh. In doing so he went utterly flat, and the arm-speed at release was quicker. It was as though he just wanted to complete his over as fast as he could. Allen, and then Glenn Phillips, treated him like a military medium pacer: stand firm in the crease and swing through the line.

When he tried to slow down, he became too slow and the ball lost its bite. Phillips had ample time to sashay down the surface and thump him past the sight-screen. He doesn't beat batsmen in flight or drop in this format; he tosses it up, and a batsman of Phillips' calibre will not miss that. When he tried to pull his length back, he at times went too short. He went wider off the crease to exaggerate the angle from around the stumps.

He was so masterful at manipulating angles that the ball would still land on middle and off, bringing leg before wicket into play. Here, a few veered down the leg-side, and some slipped out of his palm and flew as full tosses. In a nutshell, he is now exactly the bowler he doesn't want to be: one who cannot land the ball where he wants, at the pace and angle he envisions.

Allen's wicket brought relief, and suggested there could still be several games left in him. The under-cut ball gripped the surface, stopped on him, and held its line to induce a miscue. There was the double-wicket maiden against West Indies in Lucknow as well. Such instances have been rare since the World Cup.

He was never the most prolific wicket-taker. He was the enforcer who tied an end up, piled on the dot balls and built pressure. When he is not pulling the chain on runs, India are left with neither a wicket-taking aggressor nor a run-traffic controller.

Kuldeep Yadav and Varun Chakaravarthy are the two extreme alternatives in the eleven. Both are proven wicket-takers who can influence the game with a spell, but their inclusion weakens India's batting depth. Axar, though, hasn't quite starred with the bat down the order. Apart from his 63 against Sri Lanka three years ago, most of his utility knocks have come in the middle order. Naman Dhir cannot yet be trusted with four overs. There are alternatives outside the squad, such as Washington Sundar and Krunal Pandya.

More pertinently, it could just be a passing phase every cricketer endures. He is too valuable and proven a player to be discarded like a stale curry leaf. But in the immediate context of the series, the selectors have a tough riddle to solve: whether to stick or twist with Axar, a firm pillar of successive T20 World Cup-winning squads, but now shaking dangerously.