The Sunday Times reported that Media Sports Investment (MSI), the firm behind the deal that brought the players to Upton Park from Corinthians, has retained the right to determine the duo's future places of employment.

An advisor to MSI named by the newspaper as Renato Duprat, confirmed West Ham's role was to act as a "surrogate mother" for the players during their first year in Europe until a bigger club could be found.

Although West Ham retains the players' registrations for regulatory reasons, both contracts contain clauses that allow MSI to sell Tevez and Mascherano to another club with the Hammers receiving no proceeds from the sale.

Under the terms of the contract, West Ham will pay half of the players' salaries, 1.5 million pounds a year for Tevez, and 1 million pounds for Mascherano, the newspaper reported.

West Ham are also contractually obliged to start both players in the first team whenever they are fit to play.

The paper reported that West Ham does have the option to take "normal" control of the players but only if they make a prohibitively high payment of around 60 million pounds.

"If you look at West Ham's latest accounts, I think you will find that our contract values Tevez and Mascherano at more than the net value of the club," a source close to the deal told the paper.

The Sunday Times said MSI had initially offered the duo to a host of other clubs across Europe but settled on West Ham after Chelsea, Manchester United, Arsenal, Sevilla and AS Roma baulked at the asking price.

MSI chief Kia Joorabchian, who has been strongly linked with a takeover at West Ham, has denied the players will be sold at the end of the season.

And Joorabchian was quoted by the News of the World as saying that he believes West Ham have the potential to challenge the elite of English and European football over the next decade.

"I believe in the very near future West Ham can become bigger than Chelsea and maybe within seven years even challenge Manchester United," Joorabchian told the paper.