London - West Ham United pair Winston Reid and Victor Moses have been ruled out until the new year with hamstring injuries, manager Slaven Bilic revealed.
New Zealand centre-back Reid is due to undergo a scan on Friday to determine how long he will be sidelined for after injuring himself in training.
Nigerian winger Moses, on loan from Chelsea, will be out for between four and six weeks after damaging his hamstring in last weekend's goalless draw at Manchester United.
"Reid got injured in training. It doesn't look good," Bilic told a press conference. "It's one of those they tell you is four to six weeks, but it doesn't look like a small one. He slipped and felt it rupture.
"Victor is out for four to six weeks. It's a blow."
West Ham have already lost playmaker Dimitri Payet and striker Diafra Sakho until February, while attacking midfielder Manuel Lanzini was ruled out for six weeks with a thigh injury earlier this week.
Striker Enner Valencia has been out for five weeks with an ankle complaint, but could return against Stoke City on Saturday.
Faced with the injury glut, Bilic has decided to bring forward the senior squad's move to the club's new Rush Green HQ training base, which had been scheduled for the start of next season.
The Croatian, whose side are seventh in the Premier League, feels the pitches at West Ham's current Chadwell Heath base may be responsible for the rash of injuries his players have suffered.
"We were planning to move next season, at the start, to Rush Green because of the quality of the pitches," Bilic said.
"I decided on Monday next week, we will go. We can't continue to risk this much on these kind of pitches."