It started as a rumour out of a possible injury concern, but now has become a full-blown crisis of honesty, pressure from clubs and failed diplomatic negotiations.

The Wallabies beat Japan in Oita last weekend to kick off their spring tour, however the UK leg has been thrown into turmoil following the withdrawal of Samu Kerevi, Quade Cooper and Sean McMahon.

Kerevi did not play the Test against Japan after sustaining a lower-leg injury in the Wallabies' win over Argentina in their final Rugby Championship Test on the Gold Coast.

There were some early suggestions that Kerevi may choose an injury-rehab program rather than go on tour for another month, but the Wallabies management from the outset only gave indications that he, Cooper and McMahon would tour.

The short of it is none of them will tour now, and the full story will take some time to come out.

All three play for Japanese clubs. Kerevi and McMahon are on the books of powerhouse Tokyo Sungoliath (previously known as Suntory Sungoliath), while Cooper is contracted to second-division side Hanazono Kintetsu Liners.

Wallabies coach Dave Rennie has consistently said dialogue with the Japanese clubs was a priority and they wanted to reach a resolution that satisfied all parties.

Now, the Wallabies have been left behind as the biggest losers and with a nasty taste in the mouth.

Did the players genuinely put club before country?

Was there any pressure at all put on the players by the clubs?

Were the clubs actually content with the players to tour following the weeks of dialogue with Rennie? 

And why did the players let their names be read out in a tour squad if they were unsure if they would tour?

They are all valid questions, but Rennie and his coaching team now have a job to get on with and bigger fish to fry.

The Wallabies face Scotland, England and Wales over three consecutive weekends from early next month.

The inclusion of Cooper and Kerevi during the Wallabies' Rugby Championship campaign transformed the way the side played in the tournament.

Cooper dictated play on the international stage with greater authority than he had shown in his previous 70-odd Tests, while Kerevi's ability to bend the defensive line with every carry provided a new midfield platform to attack from, and from which the Wallabies flourished.

Just as a simple guide, the Wallabies averaged 2.8 tries per match across the three-Test French series in July, and the three Bledisloe Cup Tests that followed.

Once Cooper came in — and with Kerevi playing all but the Japan Test last weekend — the Wallabies scored 3.6 tries per outing over the next five matches.

The biggest challenge for the Wallabies now — with their first match of the UK leg against Scotland just over a week away — is to find a game plan that mimics what has been so successful over the last five Tests, and one that allows the players to play to their own strengths.

It is entirely unfair to ask the players now tasked with the job to keep playing to a game plan designed around Cooper and Kerevi.

Wallabies' defence proves solid

So, what parts of the current game plan can still hold and what needs to be looked at?

Certainly, the Wallabies' defence has significantly improved this season.

The Wallabies achieved around 85 per cent tackle effectiveness in the three Tests against France, which meant that, even though they dominated possession and territory in those matches, it only took a missed tackle or two during a passage in play to give Les Bleus a sniff.

They were good enough to make the most of those opportunities, as the winning margins were two points, two points and three points in the three Tests. The Wallabies scored seven tries to France's six.

Fast forward to the end of the Rugby Championship, and the Wallabies were suddenly choking teams out of the contest with their defence via truly elite levels of tackle effectiveness.

They missed just six tackles against South Africa in the 30-17 win in Brisbane, having achieved 94 per cent tackle effectiveness. They restricted the Springboks to just one try, despite the visitors enjoying 59 per cent of possession and 60 per cent of territory.

Against Japan last weekend it was a similar scenario, with the Wallabies missing just five tackles from 101 attempts. Japan's two tries for the match came from a cross-field kick to the corner, and an intercept near halfway.

The Brave Blossoms did not cause much trouble for the Wallabies' defence.

Attacking strategy needs tweaking

The other major improvement is the Wallabies are now kicking for territory more, using the space in behind their opposition to their advantage, and then keeping teams in their own half through their improved defence.

Not that long ago, the Wallabies used to dominate possession but they struggled to convert it into scoring opportunities, with opposition teams just happy to defend and wait for a mistake.

However, by playing this smarter territory game — while still generally winning possession — the Wallabies are forcing their opposition to make mistakes through their defensive pressure.

The foundations of a smart game plan are now there for the Wallabies, and their form line and confidence levels are strong enough that they will cause problems for Scotland, England and Wales.

But they will have to create different kinds of problems now.

The absence of Cooper and Kerevi means they will have to tweak the attacking strategy to one that uses more subtlety and guile from the likes of James O'Connor and Hunter Paisami — or whoever it ends up being in the centre channels — rather than the brute force Kerevi had delivered.

Without a doubt, the three upcoming Tests present the biggest challenge for the Wallabies in 2021.

They have shown themselves to be a much smarter team, with an improved defensive system to complement a consistently strong set-piece platform.

But now they must show that there is much more to the team and the way they play than just midfield destruction and sharp attack with front-foot ball.

Any wins the Wallabies achieve now will be reward for patience, for smarts and — undoubtedly — for clever coaching.