Moyes on Friday confirmed striker Louis Saha's fears that the Toffees' top goalscorer is likely to miss the rest of the season after an ankle operation.
Saha, scorer of 10 goals this term, was injured in the Barclays Premier League win over Fulham a fortnight ago and joins two other key players in Mikel Arteta and Marouane Fellaini on the sidelines.
Jack Rodwell, Tim Cahill and Seamus Coleman are also doubtful for Saturday's clash against Aston Villa at Goodison Park after withdrawing from recent international duty.
With debate raging over the merits of this week's international friendlies and whether established senior players such as Arsenal's Jack Wilshere should still play in the Under-21s, Moyes feels the top players are being overworked.
The Scot said: "To have a friendly at this stage of the season is difficult.
"I understand why the national teams want them but we are into the last six or seven weeks of the season and you can see the amount of injuries players are having, probably on the back of the World Cup and other international tournaments.
"I think that is why you are probably seeing so many injuries if you look around the Premier League."
Moyes feels so strongly about the situation he admits it has even tempered his natural pride at seeing his defenders Phil Jagielka and Leighton Baines play for England this week.
The Everton pair both started Tuesday's draw with Ghana at Wembley and at least came through unscathed.
Moyes said: "I do take a lot of pride because I want them to be selected for their country, but I am beginning to doubt if that is what I want.
"I am just beginning to look and say 'Is it worth it?'.
"We have lost quite a few players. They don't pay the players' wages, we have to.
"That is the way football is, you get injuries.
"We are picking a few up. We tend not to talk about them but we have got a fair spate of them at this moment in time."
Moyes, with a threadbare squad already due to financial restraints, could therefore have limited options for Saturday's reunion with former Liverpool boss Gerard Houllier.
The Frenchman, who is under pressure at Villa, was in charge at Anfield when Moyes took over at Everton nine years ago.
The pair may be regarded on Merseyside as old foes but Moyes claims that is far from the case.
He said: "I am really looking forward to it because I have known Gerard a long time.
"I knew him long before I got the job at Everton and he was Liverpool manager."
Aston Villa's defensive duo of Richard Dunne and James Collins are in contention for a recall at Goodison Park.
Dunne and Collins proved their fitness after shoulder and calf problems by playing for the Republic of Ireland and Wales respectively during the international break.
The duo had previously been fined by Villa because of their behaviour during a team bonding session at a health spa.
Right-back Kyle Walker is Villa's only injury concern with the slight hip problem which forced his withdrawal from the England squad.
Midfielder Ciaran Clark will complete a two-game ban for incurring 10 bookings this season.
Stewart Downing insists the Villa players have a good relationship with manager Houllier and talk of a mutiny has "been blown out of proportion".
The England winger believes it is easy to blame Houllier and blame him for Villa's slump when the squad have to take responsibility.
Villa are only one point above the bottom three ahead of the Goodison Park encounter.
Downing is also adamant Houllier has not made any wholesale changes in terms of bringing in new rules and, in any case, players have to adapt to his demands.
The former Middlesbrough player said: "The manager is fine. We all get on with him. It is easy to point at him and say `it's his fault' because he changed a few things.
"I had it at Middlesbrough before. `It was the manager's fault, it was the players' fault etc, it was his fault because he wanted to leave etc'.
"You've just got to stick together and blank it out because when it is going well, everyone will take the praise.
"It happens at every football club and we've got no problem with the manager.
"No matter who the manager is, it's down to the players at the end of the day to get results and not him."
When asked about a mutiny in the squad, Downing said: "It has been blown out of proportion. Little things go on at football clubs."
Source: DSG
