Australia could be on the verge of securing the world No.1 Test ranking in Perth, but they might have to enter the crucial third Test without pace weapon James Pattinson.
The 22-year-old was rushed for scans on a side injury after leaving the Adelaide Oval during day three of the second Test against South Africa.
It will be a nervous wait for results, but it would seem he's at least very long odds to contribute to Australia's bowling efforts in the fourth innings.
Backing up for another Test just three days later in Perth on Friday would be a big ask.
Australia can usurp South Africa for the No.1 Test ranking if they win the series.
Pattinson's explosive pace would be keenly missed on the fast bowler's paradise that is the WACA.
The Victorian, complaining of pain along his left side, left Adelaide Oval during the opening session on Saturday.
It's the latest blow in his injury-plagued career.
The express quick missed most of last summer with a foot injury and suffered from stress fractures in his back as a teenager.
He's also been forced to miss matches in the past year due to abdominal and buttocks strains.
NSW tearaway Mitchell Starc shapes as favourite to replace Pattinson should he be ruled out.
Starc has carried the drinks for Australia at the Gabba and in Adelaide and his 2012 performances in shorter-form cricket have been excellent.
WA quick Nathan Coulter-Nile, rising NSW paceman Josh Hazlewood and Victorian allrounder John Hastings would come into contention for a call-up to the national squad if Pattinson is ruled out.
However, Starc would almost certainly be the man to play.