Everton have suffered a blow with the news Tim Cahill faces three weeks out with a calf problem.
The talented midfielder picked up the injury during the Europa League win over Sporting Lisbon on Tuesday.
It means Cahill will miss the visit of Manchester United on Saturday and also the return meeting with Sporting in Portugal next week.
"Tim will be out for two to three weeks because he has got a calf strain," said Moyes.
"It is a grade one, it is not serious but I would be very surprised if he could make any of the games in this coming week."
Cahill joins Marouane Fellaini on the sidelines after the big Belgian was ruled out for the rest of the season with a serious ankle injury.