If Matthew Hayden does not decide to end his career after this match, Australia's selectors must be brave enough to finish it for him. In the increasingly likely event that South Africa win the series in Melbourne and the Sydney Test becomes a dead rubber, it would be the perfect time to audition a new partner for Simon Katich in a low-pressure situation.
It's a shame that it has come to this but Hayden's struggle has become so difficult to watch and such a concern for his middle-order colleagues that he can't go on. They are already trying to carry an unfit Andrew Symonds and a weak Hayden adds significantly to the burden. Great players earn credits at the selection table but like a blackjack player running out of chips, Hayden's failures in the Boxing Day Test have been two busts too many.
Even if Australia somehow avoid defeat at the MCG - final-day rain looks like their only chance - there is merit in throwing a fresh face into the Sydney Test. Look what happened when South Africa gave JP Duminy a chance. And with a trip to South Africa fast approaching and the Ashes in England to follow, Australia cannot support an out-of-form opener any longer.
Hayden has made two half-centuries from 15 innings since returning to the Test side for the tour of India after recovering from an ongoing heel injury. In Australia's four home Tests this summer he has 79 runs at 11.28. His lean run pales in comparison with the infamous slump of another left-hand opener, Mark Taylor, who from 1995 to 1997 went 21 Test innings without passing fifty.
Taylor was extremely fortunate to keep his position but he had two things on his side: he was the captain of a winning outfit and at 33 it was felt he had several good years left. At 37 and in a team that is starting to lose more than it wins, Hayden has neither get-out clause.
Nor is there room for sympathy. A farewell Test at the SCG would be a sentimental moment but Australian selectors have not been noted for their compassion in previous seasons. Ian Healy's last Test was in Zimbabwe and he was denied the chance to say goodbye with one final match at his home ground the Gabba.
Mark Waugh ended with a Test in Sharjah, though he didn't know it was his finale. He wanted to play on for the 2002-03 Ashes; the selectors did not pick him and he took the hint and retired. If the MCG Test turns out to be Hayden's send-off it will already be a more fitting exit than Healy and Waugh received; Melbourne has been Hayden's favourite venue.
But does the new group of selectors under Andrew Hilditch have the same clinical approach as the panel did when Trevor Hohns was in charge? They should remember that when Healy was nudged aside, his replacement Adam Gilchrist won over the Brisbane crowd by the end of his first match. The Australia players had a new match-winner in their side. Fans and team-mates move on.
And how will they ever know if there's another star waiting in first-class cricket unless they try him? The New South Wales opener Phillip Hughes, 20, is having a phenomenal season. He's the same age that AB de Villiers was when he made his Test debut and Australia need only think back a week to realise what de Villiers has learnt in four years on the international scene.
Then there's Chris Rogers, who played the Perth Test last summer before losing his Cricket Australia contract. He is 31, but a switch of states has revitalised him and he is averaging 82.62 this season. In any case, Phil Jaques should be fit by the time the Ashes comes around and he and Simon Katich can form a strong partnership. It would be useful to have a backup who has had a decent taste of the action.
When Hayden was caught driving to short cover for 23, he trudged off the MCG with his head bowed. It was not the exit he envisaged and injuries to Brett Lee and Symonds might yet save him for Sydney. Australia will be loath to lose three long-standing players in one Test.
Symonds carried a knee problem into the Boxing Day Test and was tentative in the field and unable to bowl medium-pace. His scores of 27 and 0 will increase the calls for Shane Watson to replace him. If both a hobbling Symonds and his great mate Hayden play in Sydney it will be a poor reflection on the selectors. Opportunities for risk-free change don't come often in Australian cricket. This chance cannot be let to slip.