Alan Curbishley has revealed that Mark Noble will be out for a fortnight after undergoing a hernia operation.
Freddie Ljungberg, James Collins and Dean Ashton are all back in training following injury and Curbishley hopes to be able to call on the trio soon.
But the West Ham manager admits it is frustrating to lose Noble, who has been one of his team's standout players so far this season.
The midfielder had to be substituted in last week's Carling Cup victory over Coventry and then missed the Premier League clash with Bolton on Sunday.
It was hoped that surgery would not be required but there was no other option and Noble now faces a spell on the sidelines.
"Freddie Ljungberg has trained, James Collins has trained, Dean Ashton is in training, so we are hopeful that they get through okay in the weeks to come," Curbishley, celebrating his 50th birthday, told Sky Sports News.
"But Mark Noble has had a hernia operation. He came off against Coventry feeling really sore so he's out.
"He's not going to be around for a couple of weeks.
"So we get a couple back and one goes out. That's just life at the moment."