Jacques Kallis finds himself in an odd position - in a slump, but not called on to play his customary sheet-anchor's role © Getty Images

Passenger? Now there's a funny thing.

Isn't Jacques Kallis more customarily the irreplaceable driver, in batting terms, of the Good Steam Engine South Africa? But the wheel turns fascinatingly and unpredictably in cricket. Yes, in recent times King Henry - Kallis's second name - has been ingloriously relegated to bit part in the production, if you like, of Test runs for the Proteas.

As the team he has represented with rare distinction in 125 Tests sets up camp in Perth for another series against fierce but near-hoodoo adversaries Australia, the 33-year-old's palpable lack of form ought to be a source of deep consternation.

Two or three years ago it would have been precisely that. Opponents knew that if they blasted through the No. 4 bedrock, a soft South African underbelly might not be far away. But things have gone full circle, as evidenced by the 2008 calendar year thus far: amidst South Africa's most settled top six since re-admission to the Test fold, the name of JH Kallis is the sole one not routinely up in lights.

Graeme Smith, Neil McKenzie and Hashim Amla have all gone voraciously past 1000 Test runs for the year, while Ashwell Prince has 900 on the nose and AB de Villiers 885, with two further opportunities (Perth and Melbourne) ahead to reach the mark before Auld Lang Syne. A lot of South Africans have been ripping the proverbial fox to shreds: almost surreally, Kallis is the hound labouring at the rear of the pack. He shows just 519 runs from 13 Tests and 20 innings this year, at 28.83.

What is wrong? An inevitable school of thought examines his age and suggests he's "in natural decline" or that "the eyes must be going". The ravages of time cannot be wished away, but it is hard to be convinced on those grounds when you consider that Kallis was no young buck in 2007 either - and that was his best ever year in Test-average terms (a giddy 86.42: 1210 runs in only nine Tests).

Does one go into age-related retreat so wretchedly quickly? You would think not. More plausible is the likelihood that, in this most intricate of sports, he has encountered some technical speed bumps; some issues to rudely tickle the walls of his famous "bubble".

Kallis' predecessor in South Africa's No. 4 position, Daryll Cullinan, subscribes to this view. He told the Cape Times recently that it was a question of balance: "At the point of delivery, his head seems to be outside the off stump, which is too far." Cullinan also believes Kallis will come right. "I often use Jacques as an example when I'm doing my clinics with kids… he's always had such a perfect technique. I know he'll turn the corner against the Aussies."

Some South Africans are fearful that Kallis' current vulnerabilities will be exposed by a resurgent Brett Lee, who tends to get a bee in his bonnet anyway when bowling to the resilient right-hander on Australian soil; there have been some riveting and occasionally tetchy duels.

But Kallis also has a solid Test record there, with 728 runs at almost 50, and two centuries, including his maiden one, in his 10th Test innings, at the MCG in 1997. He still counts that second-innings 101, against an attack that included both Shane Warne and Glenn McGrath, as possibly his most satisfying. It helped South Africa to stalemate safety at 273 for 7, after being set an improbable 381 to win.

Annus horribilis Kallis' batting average of 28.83 in 2008 is his lowest in a calendar year in which he's played more than five Tests. His performance this year marks a contrast to 2007, where he averaged 86.42 - his best in a calendar year. He was also the leading run-getter in the world that year, with 1210 runs in nine Tests. Kallis' slump in form in 2008 is significant as he has also failed against Bangladesh, averaging just 25.75 in four Tests against them. He didn't play a Test against Bangladesh in 2007. The modes of dismissals reflect Kallis' struggles this year. He's been bowled seven times in 20 innings in 2008, as opposed to just once in 17 last year. He's been bowled on 41 occasions in his career - that's 23.03% of his overall dismissals; for 2008 that figure is much higher, at 38.8%. Kallis played more away Tests this year than he did in 2007. Seven out of his nine Tests in 2007 were played at home, in which he averaged 65.75. His performance in the two away Tests, both in Pakistan, was even better - he made three centuries and a fifty, averaging 210.50. In contrast, he has played nine away Tests this year, managing just one century and a half-century, and averaging 24.78. He's done better at home, with an average of 43 in four Tests. South Africa have a better win-loss record in 2008 and Kallis' travails have not affected them too adversely. He's averaged 44 in their nine wins, but just 6.75 in their two losses. In 2007, however, he averaged 93.77 in South Africa's six wins and 50 in their two defeats. By Siddhartha Talya.

This writer's sixpence is that Kallis has suffered more from a crisis of identity in recent months than anything else. Strange as it may seem, the oft-rampant success of the Smith-McKenzie opening partnership, the perpetual advancement of Amla at No. 3 and the dogged durability of Prince one rung below Kallis has rendered the veteran's own long-time trench-fighting qualities virtually obsolete.

It is hardly an unwelcome phenomenon in terms of the Proteas' broad health and future prospects: where once Kallis would routinely set out his personal stall at 40 for 2, he has more recently tended to take guard with the total nearer 150 or 200 (or even well more) and the requirement much more to "get a crack on". And getting a crack on, as the world knows, is not his strongest suit. So he has possibly been feeling a little like long-distance running legend Haile Gebrselassie would if thrust into the field for the 200-metre dash: suddenly strangely out of place.

Batting in adversity is Kallis' forte, his party trick. A raft of younger players effectively hiding his magician's suitcase cheekily at the back of the dressing room is no sinister development, even if it may require him to tweak his own game plan to some degree.

Tweak it he should be urged to do - even his admirers' patience will have been tested by his particularly grim conservatism against limp Bangladesh, where his unremarkable 40 runs over two innings in the short series came at a painful strike-rate of 37.38. Poor nick as mitigation or not, the blunt truth is he "missed out".

Still, who's to say adversity won't revisit South Africa in Australia? History suggests that peril may well lurk for them there more than they would like, and the old firefighter will be summoned to his most relished responsibility once more.

He needs 199 runs and five wickets to become the first player to register both 10,000 runs and 250 wickets in Tests; Australia would be an apt place for Kallis to raise the milestone.

Woes with the blade or not, he remains a vital balancer in the South African team in his role as fourth seamer, where his "heavy ball" is still exactly that, by all accounts, and his ability to break partnerships or knock over pesky tailenders is barely dimmed. His general gnarly experience as a cricketer is also important for this series.

If Kallis is presently a sedentary passenger on the Proteas' batting train, nobody is begrudging him silver service and the finest cognac in the dining coach. Nobody, yet, wants him off at the next stop.

There are still many prongs to his arsenal, even if the main gun barrel is strangely muted.