St Lucia, August 9, 2016. India made a raft of changes to their XI, and most of the debate that ensued had to do with the shuffling they did at the top of the order. Less remarked upon, but of potentially longer-term impact, was the inclusion of Ravindra Jadeja in place of Amit Mishra.

Mishra had been preferred to Jadeja as R Ashwin's spin partner in the first two Tests of India's tour of the West Indies - the team management perhaps viewing his classic legspin as more of a threat in overseas conditions than Jadeja's fast and accurate left-arm spin. Mishra began the series fairly well, but a below-par display on the final day at Sabina Park, where West Indies batted out a draw, caused India to look to Jadeja instead.

Jadeja had missed India's last 11 away Tests, and had last played one in August 2014, at Old Trafford. St Lucia was something of an audition for him.

Ravindra Jadeja exults after dismissing Nathan Lyon Associated Press

As things turned out, he played an excellent support role in a Test match dominated by India's fast bowlers, finishing with figures of 24-9-27-1 and 5.3-1-20-2. His control was exemplary - so far, so Ravindra Jadeja - but unsurprising there were little moments in his spells that weren't exactly out of his tried-and-tested playbook.

Against the right-handers, for instance, he would fire a sequence of flat deliveries at the stumps, and then dangle one up a little higher and wider, inviting the drive away from the body. Two of his three wickets in the match came off that flighted tempter - Roston Chase caught at slip in the first innings, Jermaine Blackwood stumped in the second.

This was an unusual tactic for Jadeja, and at that point felt like a one-off experiment - this West Indies team, after all, was full of batsmen with hard hands, prone to pushing at the ball away from the body. Jadeja, though, has continued to bowl this way even in home conditions. His fundamentals remain unchanged, but he has expanded the canvas of his bowling to include subtle variations in pace and angle.

Right-hand batsmen against Jadeja - shot direction Series leg side off side total LS% OS% Eng home 2012-13 162 235 397 40.80 59.19 Aus home 2013-14 278 396 674 41.24 58.75 SA away 2013-14 104 178 282 36.87 63.12 NZ away 2013-14 215 224 439 48.97 51.02 Eng away 2014 167 229 396 42.17 57.82 SA home 2015-16 232 355 587 39.52 60.47 WI away 2016 40 82 122 32.78 67.21 NZ home 2016-17 181 361 542 33.39 66.60 Eng home 2016-17 334 664 998 33.46 66.53 Ban home 2016-17 100 212 312 32.05 67.94 Aus home 2016-17 83 171 254 32.67 67.32

There is one set of numbers that bears out this change. ESPNcricinfo's scorers record a wide range of data for every ball played, including which part of the ground the ball went towards. In every series Jadeja played until the end of 2015 (leaving out balls recorded as going into a "not specified" zone - usually balls left alone or dead-batted or played straight back towards the bowler), right-hand batsmen invariably ended up with a roughly 60-40 split between shots going into the off side and shots going into the leg side. This was in keeping with Jadeja being someone who attacked the stumps and turned the ball away from the right-hander, though not to a great degree.

Since the start of 2016, however, right-hand batsmen have been playing Jadeja differently. Now the split is closer to 67-33, a significant drop in the ratio of balls played into the leg side. It's more in line with how they would play a classic left-arm spinner.

Ravindra Jadeja - dismissal summary bowled % lbw % c keeper % c fielder % stumped % total up to Dec 31, 2015 22 32.35 10 14.70 6 8.82 27 39.70 3 4.41 68 since Jan 1, 2016 4 6.55 18 29.50 7 11.47 28 45.90 4 6.55 61

Jadeja's wicket-taking methods have changed too. He's getting far fewer batsmen out bowled, a greater percentage out lbw, and more batsmen out caught. Analysing his dismissals of right-hand batsmen, in particular, reveals the extent of his evolution.

Until the end of 2015, he dismissed 49 right-hand batsmen, of whom 25 (51.02%) were bowled or lbw and 11 (22.45%) caught by the keeper, slip or gully. Since the start of 2016, he has dismissed 36 right-hand batsmen, of whom 16 (44.44%) have been out bowled or lbw, and 11 (30.56%) caught by the keeper, slip or gully.

Where he had five right-hand batsmen (10.2%) caught at short leg, midwicket or mid-on in the first half of his career, he has only had two (5.55%) caught at these positions in the second half. Where he didn't get a single right-hand batsman caught at silly point, cover or mid-off until the end of 2015, he has dismissed four of them in these positions since.

The change in bowling style hasn't dulled his effectiveness in any way. He took 68 wickets at an average of 23.76 and a strike rate of 62.70 in the first half of his career. In the second half he has taken 61 wickets at 23.09 and 61.0. His economy rate, across avatars, has remained exactly the same: 2.27.

Perhaps Jadeja's inability to run through Australia in Pune - where conditions were tailor-made for his 2012-2015 version - was down to his becoming a more classic left-arm spinner. He found it difficult to operate away from a traditional good length, and often ended up turning the ball far too much and, as a consequence, missing the outside edge.

India coach Anil Kumble takes pictures during the warm-up match AFP

At the same time, though, Jadeja now looks more threatening on flat pitches than he used to, his changes of pace and trajectory keeping batsmen vigilant at all times where his earlier, metronomic style could occasionally bowl them into a rhythm.

Now, if he sees a batsman negotiating him largely off the back foot, he'll aim a round-arm dart at his pads. Or if a batsman is defending him off the front foot with his pad next to the line of the ball, wary of the threat of lbw, he'll toss one up slower and wider. Sometimes, this may bring immediate results - think Jonny Bairstow scooping a catch to short cover in the first innings in Chennai. At other times, a batsman may simply slice the ball to backward point, off the outside half of his bat, then start bringing his front leg further across in defence, leading to an lbw further down the line.

The changes in Jadeja's bowling have been subtle and can be easy to miss. He has kept quiet about them - or hasn't been asked about them - unlike Ashwin, who talks often, and in depth, about his bowling. Perhaps Jadeja is happy to pass under the radar and let the world continue to think of him as an uncomplicated stump-to-stump metronome. That won't last too long though, given he now sits right next to Ashwin on top of the ICC's Test bowling rankings.

One question remains: what triggered the shift in Jadeja's bowling? What changed between his 16th Test against South Africa in Delhi and his 17th in St Lucia eight months later? One thing did change: India hired a new coach, and that man, Anil Kumble, had a career of two distinct halves. In the first half, he was a fast, non-turning legspinner who speared the ball into the stumps and let the pitch do the rest. In the second, he began flighting the ball more, varied his pace more frequently, and tasted far more success overseas. Jadeja could well be taking the first few steps of a similar journey.