(CNN) -- The transfer window opened on Thursday with West Ham chief executive Scott Duxbury admitting that the Premier League club are open to offers for every member of their squad.
West Ham manager Gianfranco Zola will be hoping he can hold on to his top stars.
The Hammers picked up two wins over the Christmas period to move into the top half of the table, but doubts remain over their financial health with Icelandic owner Bjorogolfur Gudmundsson suffering major losses due to the global economic crisis.
West Ham are also facing the prospect of a massive compensation payment to Sheffield United over the Carlos Tevez affair, leaving new manager Gianfranco Zola with a struggle to hold on to all his top players.
Striker Craig Bellamy has already attracted public interest from Tottenham Hotspur while goalkeeper Robert Green, central defender Matthew Upson and midfielder Scott Parker are being linked with a move away from Upton Park.
Duxbury told the club's offficial Web site that Zola would have final say on any departures.
"We must not be afraid of interest in or bids for our leading players," Duxbury said.
"Each approach will be considered in terms of fee, fitness, form and where the manager thinks the player is in his career.
"We have to consider the will of the player and whether he is committed to what we are trying to achieve.
"A bid may be evaluated by the manager as allowing him to significantly improve his team."
Duxbury claimed that former Italy star Zola wanted a slimmer first team squad based on "quality over quantity"
Meanwile, fellow Premier League side Portsmouth have said that former Arsenal star Lauren and Richard Duffy can leave in January.
Pompey are another side rumored to be in financial difficulties, but chief executive Peter Storrie told the Portsmouth News that the club were looking to bring in "two or three during the transfer window to improve the squad."
"I never talk about money but Tony (Adams) will be given the means if he wants to strengthen the squad," he added.
Portsmouth pulled in nearly $30 million with the sale of Lassana Diarra to Real Madrid, but striker Jermain Defoe is another being linked with a move, his former club Tottenham the leading suitors.
Manchester City are expected to be the biggest spenders in the transfer window as the Premier League club's Abu Dhabi paymasters flex their financial muscle.
Brazilian star Robinho was signed from Real Madrid in the last day of the summer window just after the new owners took control and manager Mark Hughes is keen to strengthen his squad.
Premier League clubs shelled out over $200 million in the last January transfer window, but it is unclear if this will be surpassed this year as the global downturn bites, coupled with a strong euro.