Australia captain Michael Clarke has suffered a recurrence of his chronic back problem and is doubtful for the NatWest Series decider against England at the Ageas Bowl.
The tourists already know they will have to make one enforced change and it seems likely they will recall opener Phil Hughes in place of Shaun Marsh - who is ruled out after hurting his hamstring in the fourth match of five in Cardiff.
After England levelled the series at 1-1 there, Clarke is still hoping to play but will be allowed to do so only if he is thought fully fit. Coach Darren Lehmann spelled that out as he assessed Australia's selection options.
"It's a big game. But if he's not right, we won't risk him," Lehmann said of Clarke. "It's an important series, but we've got another one-day series (against India) and an Ashes series coming up."
As for Hughes, who last played for Australia in the second Test at Lord's, the coach added: "We'll look at the pitch, but I think that's the probably the way we'd go.
"It gives him an opportunity. He's playing really well and working on his game, and that's all we can ask. He's ready to go. We hope he gets his chance and away he goes."
Should Clarke be unavailable, Australia may call all-rounder Glenn Maxwell into their squad for the first time in the series, with room too perhaps for the return of leg-spinner Fawad Ahmed.
Australia have endured a disappointing tour, an early exit in the Champions Trophy being followed by a 3-0 Ashes defeat and then a 1-1 draw in two Twenty20s.
Lehmann said: "It gets down to a grand final set-up now - which is great. That's what we want the players put under most of the time, although you would have loved to close out the series (in Cardiff).
"We're certainly playing the right brand of cricket. We just made a couple of elementary mistakes.
"Apart from that, we've pretty much played how we want to play. Now the case is we want to finish on a high and get moving on."