James McCarthy could miss the Republic of Ireland’s vital World Cup qualifier against Wales at the Aviva Stadium later this month.
The midfielder played no part in Everton’s 3-0 victory over West Brom.
A hamstring injury looks set to sideline the 27-year-old for up-to two weeks, the Boys in Green face Wales on March 24th.
“James is again with some problems on his hamstring, it happened in the beginning of last week.
“It’s painful for the boy by himself but also for me because I like him and we like to progress with him.
“Every time we get a step back. It’s not a big hamstring maybe he will be out for one or two weeks - but I’m really disappointed about it.
“We need to deal with his fitness and maybe 30-35 minutes (play him) like last week, then put him in recovery group after the game.
“We need to learn. I’m not a doctor but I want the best for him, it’s difficult.
“It’s another step back for the boy and that’s really disappointing. We need to find a solution and we haven’t found it yet.”
Koeman doesn't believe McCarthy will be fit, but expects him to be called up nonetheless:
“I don't know. We know it will be another nine, 10 days before the game and the FIFA rule is that they have the possibility to call the player.
“If they call the player the player will go and they will see how his fitness is at that time."