The fate of a series could depend on events in Potchefstroom today. By this evening, maybe earlier but not much later, South Africa will know whether their star all-rounder Jacques Kallis will be fit for the First Test.
They will be tempted, as their three-day training camp comes to an end in the university town where Dame Kelly Holmes trained for double Olympic gold, to seek another adjournment if it is necessary. But the match begins on Wednesday. Decisions will have to be made.
It is all a replica of the angst England have experienced so often in the past when doubts surrounded Andrew Flintoff. Perhaps it is a more extreme version of the condition. Kallis is the rock on which South Africa's side is built. Since he made his debut in December 1995, South Africa have played 147 Test matches, only 16 without him.
His broken rib, sustained in the Champions League in India (who says Twenty20 doesn't have a lot to answer for?) and aggravated when he subsequently played in the Champions Trophy and in a Twenty20 international against England at the start of this tour, is taking its time to mend. That is the way with ribs.
South Africa have made confident noises but Kallis has had to resort to an oxygen chamber to accelerate the healing process, a sure sign that all is not going according to plan. There are suggestions that not only is he a doubt for the opening match but for the whole series. Mixed messages from inside the camp – in one breath he could play as a batsman only, in another that could not be countenanced because he would still be affected by the injury – invite suspicion.
Kallis' absence would disrupt the side. With him as the bulwark of the batting and a trusty fourth seamer, South Africa are formidable. Without him they have to worry about how many batsmen to play and how many bowlers, or if there is another all-rounder up to it (there isn't). The matters of 10,277 runs and 248 wickets are not easy to replace.
The batting, starting with estimable captain Graeme Smith, would remain strong but someone would have to play the holding role. South Africa are desperate to win this series, partly to atone for losing to England at home five years ago, partly to redeem themselves after somehow losing to Australia in March having beaten them away and partly to try to reclaim the No 1 spot in the world rankings of which they were recently deprived by India. Their favoured team has been known from a long way out.
Their personable coach, Mickey Arthur, made no secret of his preferred side, which included the high velocity but contrasting bowling of Dale Steyn and Morne Morkel. The third seamer will be Makhaya Ntini, playing his 100th Test, but he is in decline, well down on pace. But, Kallis or no Kallis, they look undercooked. Five of the intended side have played not a single first-class match since the last Test against Australia in March.
Smith embodies the nature of modern cricket, particularly among South Africa's players. Since July 2005, he has played 40 first-class matches, 38 of which have been Tests. The last time he played in a first-class match at home other than a Test was in October 2004 for Western Province-Boland, when he made 200.
Smith has found a way of coping, as doubtless he will again. But it provides a chink of light for England whose own preparation has been far from ideal in the past few days. If Kallis fails to make it on Wednesday – and his chances are slim – the chink will become a window of opportunity.