West Ham boss Alan Curbishley admits he will need to sign another defender before the closure of the transfer window after revealing the club have accepted a bid from Sunderland for Anton Ferdinand.
The 23-year-old defender is reportedly considering the offer, thought to involve a fee of around £8million.
Curbishley, whose team yesterday lost 3-0 in the Barclays Premier League at Manchester City, told BBC Radio 5 Live: 'The board have accepted the bid - he's not renegotiated his contract - and the decision was taken out of my hands.
'I don't know where Anton is in terms of signing for Sunderland - but once the club accept the bid it moves on.'
Ferdinand's current contract is set to end in 2010 and Curbishley insisted only three days ago the brother of Manchester United captain Rio was part of his plans for the Hammers.
The transfer window closes on September 1 and Curbishley will need to sign another defender to replace Ferdinand.
Fellow centre-back James Collins is on the road to recovery following a serious injury and played in a friendly against QPR while Jonathan Spector, youngster James Tomkins and Daniel Gabbidon are also unavailable because of injury.
'We are thin on the ground,' Curbishley admitted. 'If we lose another defender we will have to react to that.'
Ferdinand will be Sunderland's seventh major signing of the summer following the arrivals at the Stadium of Light of strikers Djibril Cisse, David Healy and El-Hadji Diouf as well as Teemu Tainio, Pascal Chimbonda and Steed Malbranque.