Everton manager David Moyes has confirmed that midfielder Darron Gibson will be out for up to five weeks after picking up a thigh strain.
Gibson, 24, has played in all three of his side's league matches this season and could now be forced to sit out as many as six games.
However Moyes is confident his player could return sooner than expected.
"Darron's got a thigh strain and will probably be out for four to five weeks now," he said. "He's had two weeks now so hopefully we are a couple of weeks down the line already because of the international break - so he may have only a couple of weeks to miss.''
The Republic of Ireland man recently told his national boss Giovanni Trapattoni that he did not want to be considered for selection for their World Cup qualifying campaign, after suffering from the disappointment of playing a limited role at Euro 2012.
Gibson joined the Toffees from Manchester United in January for £500,000 after struggling to break into Sir Alex Ferguson's first-team plans.