Everton midfielder Mikel Arteta has suffered a setback in his recovery from a serious knee injury, manager David Moyes has confirmed.
Arteta snapped a cruciate ligament during a match against Newcastle in February.
He was expected to step up his rehabilitation in the next month only to suffer an infection in the injury.
Moyes said: "We have had to wash out the knee. It is a setback but I cannot say for how long."
Meanwhile, Tim Cahill has been named in the Australia squad to face Oman in a 2011 Asian Cup qualifier, despite the reservations of Everton manager Moyes.
The 29-year-old midfielder has endured a heavy workload lately, having played in all but two of the Toffees' matches this season, and has been a regular for the Socceroos during their 2010 World Cup qualifiers and Asian Cup commitments.
Moyes has voiced concerns Cahill is in danger of suffering burn-out, but Australia manager Pim Verbeek has decided to name him in his 23-man squad for the Oman match on November 14.