It don't mean a thing, if it ain't got that swing
It don't mean a thing, all you got to do is sing

The tune was Duke Ellington's and the lyrics came from Irving Mills, but one of the greatest jazz standards could have been written about Mitchell Starc. He has pursued it, at times mastered it, then lost and regained it at various points of his career, but when Starc captures swing and wraps it in a yorker delivered at 150 kilometres per hour, it is one of cricket's most potent weapons.

It was one of Australia's most valuable, too, at the 2015 Men's World Cup and earned Starc the Player of the Tournament honours. His 22 wickets came at an average of 10.18 and with a giddy economy rate of 3.50. And it was Starc who struck the most devastating blow in the final against New Zealand in the very first over, that trademark swinging yorker obliterating the stumps of Brendon McCullum.

Since then, the swing has come and gone in tune with form and injuries. And now, four years after a tournament in which he was at times unplayable, the question swirls: does he have it?

"It was four years ago so a lot's changed in four years," said Starc before Australia's training session in Southampton. "I guess I'm four years older and things have changed throughout my action over those four years I think, whether consciously doing them or not and going through a few niggles and injuries which have probably affected that as well. So the last three or four months have not been focused on the last World Cup. It's about how I'm going at the minute and what I can do to get myself in the best position to help the team out going forward."

Starc hasn't played an ODI since November, at home against South Africa. But there were signs he was rediscovering a more consistent inswinger with the red Kookaburra during the Test series against India and Sri Lanka over the Australian summer. The left-armer worked closely with then Australia bowling coach, David Saker, overcoming a tendency to collapse on his front foot, something that had crept in following a string of niggles.

But a 10-wicket haul during the second Test against Sri Lanka in Canberra came at a significant cost; Starc tore a pectoral muscle and has worked his way back to full match fitness in time for the World Cup.

"I've done a fair bit of work since Canberra," said Starc. "Obviously I had a fair bit of rehabilitation straight after that and didn't bowl for a while. But having three months to chat about things and then I guess just have a little bit of a different approach to how I think about it and perhaps the change of wording and I guess my cues going forward have helped me coming back to this stage as well.

"So it's been a nice little period and things that I can focus on. I think I mentioned a little while ago just having a finer focus on a certain couple of things which are really helping me."

Errrrr… come again? If the previous paragraph reads like a well tossed word salad with a sprinkling of non sequitur croutons, it's because Starc is admitting to journalists that he's made some tweaks without giving away any clues as to what those tweaks actually are.

Let's try coming at it from another angle. Are those cues mental or physical?

"I think you could probably classify them as both," said Starc. "They're just little things I can control throughout my action and run up that help me get in a really good position and a finer focus to get that result at the other end. So they're just things I can control and I've been working on, I guess, the last few months is the feeling of it. So getting that really positive feeling of being in those certain positions or those certain cues so it's something I've really enjoyed working on and having that finer focus on those few things has really helped me."

So there's a finer focus, a positive feeling and good positions. Whatever else might be involved may become clearer during Australia's three warm-up matches and throughout Starc's World Cup campaign. And with the two white Kookaburras offering minimal assistance to swing bowlers, perhaps Starc can take his inspiration from Duke and Irv.

It makes no difference if it's sweet or hot
Give that rhythm everything you've got