And he promptly displayed his immense talent to the world by smashing an unbeaten century from just 38 balls for the King's XI in the Indian Premier League (IPL). Such form is hard to ignore, even if it is in a domestic tournament.
That Kallis's decision to make himself unavailable was criticised by supporters desperate for success is understandable, but it also reveals an equally understandable lack of appreciation for the demands made on international cricketers.
Physically, Kallis is battling no more than the "usual" niggles and strains. But as he approaches the end of his second decade at the highest level of the game, it's hardly surprising that he feels the need to "take stock of the situation".
So many players at his stage of their careers have continued because they fear facing what lies on the other side of life. If they are lucky, form deserts them and the decision to retire is made easier. Or even made for them. But none of Kallis's skills have deserted him, and he is aware of that. His desire to play in the 2015 World Cup was always based on the proviso that he was worth his place.
Whereas ambitious junior players might jeopardise the team's chances by not admitting the seriousness of an injury – or a lack of focus caused by a personal lack of equilibrium – a senior player has the courage to know whether he is likely to fulfil his value. That his decision was made less than a week before the squad was announced is immaterial. Many a bride or groom has been left at the altar in the interests of future peace.
Sceptics have pointed to the million-dollar bundle he earns in the IPL as the reason for his involvement with the Kolkata Knight Riders and suggestions that he has placed cash above country have not been thin on the ground. In some aspects, he is his own worst enemy in this regard.
Potential effectiveness
If the price of privacy is uninformed derision, then Kallis has been reluctantly prepared to pay it for most of his career. He is not immune to criticism, however. Suggestions that he is not committed to the Proteas cut deep. His view is that it takes a greater commitment to be honest about your potential effectiveness than to accept a place when you know it is compromised.
At the most, Kallis has a little over 20 months of his career left. All his life he has been organised and structured, planning each and every year, one by one. On the few occasions he has allowed the roller coaster to dictate terms, he has suffered – and so has the team. "I need to plan the end of my career. I have always played my best cricket when I know exactly what the plan is and where I am heading," Kallis said this week. "There's no point being in the squad if I'm not 100% focused."
Miller, naturally, lacks nothing in focus. He has a golden opportunity to become the power hitter the national team has lacked since the all-too-brief days of Albie Morkel at his best. Gary Kirsten has made no secret of his belief that the national team was missing an explosive "Xfactor" but felt that Miller had not taken his chances. Perhaps he had not been primed to take them? His remarkable form, and consistency, in the IPL must surely have persuaded Kirsten to make use of him at number six in the batting order.
Colin Ingram has done enough to be considered at number three but that leaves just two places between AB de Villiers, Faf du Plessis and JP Duminy. Ryan McLaren, who has done everything possible to secure the all-rounder spot at number seven, could have been sacrificed to make way for the batting strength if Kallis had been around. But he isn't. The solution might be to allow Ingram to open with Hashim Amla in place of the injured Graeme Smith.
The playing regulations, which now have five compulsory fielders inside the 30m inner circle, has made life extremely hard for part-time bowlers and most teams have opted for five frontliners as a result – or at least four and two very good part-timers. Though Du Plessis, Ingram and reserve batsman Farhaan Behardien all bowl a bit, only Duminy can be considered a serious option in the attack. Remarkably, given its rich tradition of producing all-rounders, South Africa's squad for this tournament is unusually short of them.
The Proteas have enough individuals of rare brilliance to win this tournament. And the fact that it takes just five games to do so counts in their favour. What is unusual is that they will not be starting it among the bookmakers' favourites. Perhaps that will work in their favour.