Cahill missed Everton's shock fifth-round FA Cup exit at the hands of Reading on Tuesday and only featured as a substitute in the Toffees' last Premier League fixture on the weekend.

It is a bitter blow for Everton, who have also been rocked by news that midfielder Marouane Fellaini will miss the rest of the season following ankle surgery.

Belgium international Fellaini sat out the final three months of last season with an ankle ligament injury and six weeks of this season with a hamstring problem.

He sustained the latest knock during Everton's 2-0 win over Sunderland on Saturday.

The 23-year-old will undergo surgery next week and is not expected to be available again this season.

"Marouane is going to be out for the season now, he will have an operation on Monday," Moyes said.

"Everybody who has watched us will tell you he has been a key player for us and Tim Cahill will probably miss two or three weeks as well."

Everton beat English Premier League title holders Chelsea in the fourth round, but went down 1-0 against second-tier opposition Reading at Goodison Park on Tuesday.

"It's a massive disappointment for us because we did so well in the previous round," Moyes said.

"You can only ask for a home tie and we didn't take advantage of it."

"We could have defended the set-piece for the goal, our attacking wasn't good enough. I think they defended really well."

"They got back behind the ball and we didn't have enough craft at the top of the pitch to make things happen."