Mitchell Starc grabbed at his right hamstring during his only over of India's second innings at the Gabba before rain curtailed the penultimate day of the Border-Gavaskar series. That meant Australia were left with another headache entering a final day where they must win in order to keep on top of their ambitions to reach the World Test Championship final.
Starc had begun strongly in the series opener at the Adelaide Oval but has since struggled to find his best, with his best bowling limited to just a few outstanding spells across the four matches. His obvious discomfort in the closing passage of play raised concerns that the mental fatigue of the series had a physical equivalent for one of the home side's fast men right at the pivotal point of the decider.
"I saw the same thing walking back - he was grabbing at his right hamstring I think it was, so I'm sure he'll get assessed by the medical staff," Steven Smith said of Starc. "One thing I know about Mitchell is he's tough and he's played through some injuries before and got the job done, so he'll be hopefully good to go tomorrow."
As talks around the looming tour of South Africa continue, Tim Paine's team finds itself under concerted pressure to force a result, even as the Brisbane weather forecast indicated that another hefty chunk of overs will likely be lost on the final day with India still having all ten wickets in hand in a notional chase of 328 for victory.
While India's major injury toll has forced the tourists to shuffle through an enormous number of players - particularly their bowlers - ending the series with an attack no one could have predicted when the contest began in Adelaide, the hosts have stuck with the same bowling attack in spite of the tight schedule.
Concerns about the volume of overs the bowlers could potentially be bowling once again - after sending down 131 overs in the fourth innings of the first of back-to-back Tests at the SCG - appeared one of the factors in the thinking of the Australians. That may have been a reason for them to bat all the way down to Nos. 10 and 11 at the Gabba, defying the inevitable arrival of rain.
"It's hard to know. Obviously with the rain coming, we're certainly not weathermen and don't know it's coming, so you have to play the game as you see it as well," Smith said. "I think the game's in a nice place for us. The wicket's started to play a few tricks today, a couple of balls shot up. So tomorrow I think it's just going to be about bowling good areas and letting the natural variation of the day five wicket do its work and hopefully we can hold on to all the chances.
"The Indian players have batted well. In Sydney we bowled 130 overs - obviously a different wicket to that [Brisbane] - but for us, it is just about being patient, not searching too much, bowling good areas and just letting it happen. I think the more you go searching for it on these kinds of tracks, then you probably don't get the rewards. So it's about hitting good areas consistently and letting the natural variation of the wicket take its course."
Asked directly about the "conservative" approach of the team, Smith made it abundantly clear he was not part of leadership discussions. "I'm not too sure, I wasn't involved in those conversations," Smith said of Australia's declaration. "I think the wicket's certainly different to what it is in Sydney. There's a bit more happening here. We saw a few balls hoot up today, a couple kept a bit low, [and] a couple went off cracks, which is always playing on the batters' mind. So for us it's about hitting really good areas and being nice and patient.
That said, he held out hope that Nathan Lyon might be able to figure on the last day of a series in which he has struggled for traction and has been outbowled by both R Ashwin and Washington Sundar.
"There's a nice crack forming outside the right-hander's off stump that [Lyon] will probably be looking to aim at I assume, that's a nice line. If he hits good areas consistently tomorrow, there's certainly no reason why he can't create some chances on a day-five wicket."
Daniel Brettig is an assistant editor at ESPNcricinfo. @danbrettig