Chile's midfield star Arturo Vidal is a doubt to face Australia in Cuiaba as he battles a knee inflamation, La Roja's medical staff revealed at their Belo Horizonte camp Saturday.
Vidal only just made the squad to face the Australians, Spain and the Netherlands following knee surgery last month and he is still recuperating.
"The tests showed up inflammation from the surgery, albeit within the expected parameters at this stage of recovery" from the surgery, said team doctor Giovanni Carcuro.
He insisted: "We are calm because there is only low level inflammation, which is normal."
Vidal had surgery on May 6 and then travelled to Brazil but has not been training and played barely 15 minutes of a midweek warm-up win over Northern Ireland.
Carcuro said he was optimistic but added the team would have to wait and see how Vidal's knee is nearer to Friday's game against the Socceroos.