If you were to make a T20 cricketer from scratch, you'd make a brilliant athlete with the ability to do insane things, who slogs, and loves to slog, who also bowls one of T20s most useful styles in a quick and reasonably accurate way. That's an excellent package. That's Ravi Jadeja, the man who went for over $US2 million in the 2012 auction.

There are no numbers that show Jadeja to be a top T20 player. By independent analyst Mainuddin Ahmad Jonas' Runs Above Average (RAA) metric, Jadeja is worth -4.8 runs a game. That's bad for a fill-in, let alone a star. His true strike rate suggests that when he bats he is worth -1.6 runs an over. Since the start of 2015, Jadeja's smart bowling economy (which takes into account match run rate, plus the phase when the overs were bowled) is 8.3, and he averages 40 with the ball. All of this is okay for a low-paid fringe player, but Chennai Super Kings chose to retain him along with MS Dhoni and Suresh Raina. Washington Sundar, a Tamil Nadu native, is a fingerspinner who can bat a little. Last year he took his wickets at 23, with an econ of 6.16 - a better season than Jadeja's has had since 2009.

Jadeja has only ever had one year when he took wickets at an average better than 25 and an economy rate lower than 7.5. Sometimes he has taken wickets, sometimes he has a lowish economy. But it has not been consistent. For a player with the talent of Jadeja, you'd expect him to be regularly good and occasionally brilliant.

While you can see the romance in Super Kings wanting to get the band back together, Jadeja is still a weird choice. He was, at best, the third guitarist who did occasional backing vocals. In the early days of the IPL, you could see why a team might get excited for what he could do, but now we have seen what he can do.

This is Sir Ravi Jadeja, flashing his bat like a sword, performing near inhuman fielding off his own bowling and last year he took something like seven billion Test wickets. Those wickets were in India, on Indian pitches.

Now, T20 pitches aren't Test wickets; he isn't bowling into Mitchell Starc's footmarks that often. But Jadeja averages 26 in first innings of Tests, so he's no crumbled-pitch bully. He also averages 29 with the bat overall, and while the three first-class triple-hundreds might have given us false confidence in his batting, he has still shown some flair with memorable attacking innings.

Jadeja should be good in T20. Why isn't he?

When I tweeted about how it confused me that he wasn't better, I got a boatload of reasons. I was told many things: from him struggling with the Kookaburra ball, his need for MS Dhoni to captain him, the fact that he hasn't been playing in Chennai, that he's too accurate, that he has no trick balls, that he bowls one pace too much.

Slow left-arm fingerspinners are T20's second favourite spinners, after leggies. Check the lowest economy rates of any T20 league and you'll see them there. Part of the reason is their angle. Another is their accuracy. Slow left-arm bowlers generally have few tricks, just spinning balls and non-spinning ones. But they have been incredibly successful in all T20. In the IPL their economy is 7.53, just a fraction above the 7.47 mark of all bowlers.

Many quality slow left-arm bowlers have done well in T20. But not all left-arm fingerspin is the same, or even similar. Michael Beer and Michael Yardy are strong, almost fast-bowler strong, making them hard to get away. Playing such spinners off the back foot is always difficult. Imad Wasim and Dan Vettori have height; Vettori also had a stellar bowling brain. Pragyan Ojha and Rangana Herath use flight.

Of all the better T20 left-arm spinners, the nearest neighbour to Jadeja by bowling type is Shakib Al Hasan: a low bowling action, lots of revs, and not entirely as accurate as some of the other bowlers mentioned before. But Shakib's career IPL smart economy rate is 6.8 and his average 25. Jadeja's is 7.8 and 30. Shakib is a tough player to be compared to, but when your Test bowling average is 23, as Jadeja's is, people will expect more.

For years the joke was that Dhoni controlled Jadeja like a sock puppet, telling him where and how to bowl. That narrative fell apart when Jadeja tore out hearts last winter without Dhoni behind the stumps. This year Dhoni and Jadeja have been reunited in the IPL, but in his first four games Jadeja has bowled only four overs, which is remarkable. It seems like he is a sixth bowler and lower-order anchor.

Whether or not Dhoni affects him, Jadeja is better in Chennai. At the MA Chidambaram Stadium, his smart economy drops by a run, to 7.8, but his bowling average is still 34. So he is better, but those numbers are still below Ojha's career numbers: bowling average of 26 and smart economy of 7.4. And Ojha hasn't played in the IPL since 2015 (despite being the all-time leading wicket-taker among left-arm spinners in the tournament).

As an ODI bowler Jadeja is no dud. He was outstanding in the 2013 Champions Trophy, and his career economy is 4.9. And while he has been poor since the last World Cup (taking his wickets at an average of 67), from 2012 to the start of 2015, he claimed his wickets at 31 each, and had an economy of 4.7. This shows that he can bowl with a white Kookaburra, although his overall average of 35 suggests that he just doesn't take wickets with the white ball that much.

Then there's the varying of speeds. People have knocked Jadeja partly for being a spin-bowling automaton - a wind-up spinning toy of destruction; that he doesn't have the cunning or guile of a crafty turner, that he has a quick action while still getting a lot of spin. Looking at speed analysis from CricViz, it shows how little he varies his pace compared to someone like R Ashwin. And also when he changes his pace, it's more stark. It doesn't have the subtlety or range of a bowler like Ashwin. He is much the same way with his lengths and lines, meaning that unless it is turning sharply, if you hit through the line, he's often more like a medium-pacer than a spinner. That said, bowling quality spin fast is successful in T20, but sadly, not for Jadeja.

Then there is the case of when he bowls. Slow left-arm is bowled a lot in the Powerplay. Of the top six left-arm spinner wicket-takers in IPL history, Ojha bowls 12% in that period, Shakib 29%, Axar Patel 13%, Shadab Jakati 9% and Iqbal Abdulla 30%. Jadeja bowls 5% of his overs in the Powerplay. And when he has, his smart economy is 10.3 (more than a run worse than the others), although he strikes every 19 balls, which is excellent for anyone, especially him. But costing so many runs means teams won't want to bowl him there.

The one section of the game Jadeja is superb in is bowling at the death. He bowls 30% of his overs there, and his smart economy is 8.4. Jasprit Bumrah, who has an excellent reputation as a death bowler, has a smart economy of 8.3. With Jadeja's death record being so good, and his middle-overs record being so poor, you can't help but wonder if he is being underbowled in the last five.

And last, we have his batting. Jadeja makes runs. He averages 24 in the IPL; it's just that the runs come slow. He strikes at 123, his smart economy is practically the same, which is an incredibly low strike rate for someone who bats 49.5% of their career at the death.

Perhaps the reason is that when Jadeja bats in Test or first-class cricket, the field is up, so he can slash and swing freely over the ring. When he comes in for his T20 (or ODI) innings, all the fielders are back, so he can knock the ball around, but the freedom of his occasional entertaining Test cameos is gone.

And Jadeja doesn't have monstrous power; if you block his hitting zones, it's difficult for him to hit boundaries. Because of this, he strikes one every 7.75 balls. Of IPL players with over 500 runs, it's the fifth worst ever. So while his dot-ball percentage of 37 is actually really good (21st all time), with so few boundaries, his strike rate barely gets going. Perhaps he could improvise more than he does, or maybe he should be a pinch-hitter with the field up, but his impact on games with the bat is mostly negative.

At the moment, as a bowler, Jadeja doesn't really stop runs. He is only good in one part of the innings, he rarely takes wickets, and as a batsman he is slow and steady (emphasis on the slow). But we've seen so many players with far less natural talent thrive in T20 and the IPL. Not to mention so many other players who have worked out T20 cricket later in their careers.

Jadeja played his first T20 match over a decade ago. He has played 142 IPL matches and 200 T20s altogether, and no one has bowled more overs of left-arm spin in the IPL than him. Worldwide he has bowled the sixth-most left-arm spin overs in T20. Looking at the aggregate record of IPL left-arm fingerspinners, their economy is 7.5 and they average 30.7. Jadeja's is 7.8 and 31.

The question isn't whether Jadeja is talented. It's that how someone with this much talent has ended up being below average in T20.

Jarrod Kimber is a writer for ESPNcricinfo. @ajarrodkimber