West Ham have emerged as favourites to land Mexico winger Pablo Barrera, with Premier League rivals Everton also chasing the Pumas flyer.[LNB] Spanish side Espanyol had been leading the chase for Barrera, who impressed at this summer's World Cup finals, and opened talks with his club UNAM Pumas last month.[LNB]But there is now strong interest emanating from Britain with West Ham, Everton and Celtic all reported to be keen, along with Italian side Lazio.[LNB]Pumas have now confirmed that they are considering three offers - from West Ham, Everton and Espanyol - with one bid standing out.[LNB]Reports in Mexico claim that the best offer is from Upton Park and they are now in pole position to claim his signature.[LNB]"We don't want to be making announcements when it's not the correct moment. When everything is OK we will make an announcement," said Pumas director of sport Mario Trejo.[LNB]"It's very possible that between Thursday and Friday we will have something more serious to say. [LNB]"If there is an important announcement to be made, the president will be in charge of letting everyone know.[LNB]"I must admit that after analysing the offers of Espanyol, West Ham and Everton, there is one that has convinced us more than the rest.[LNB]"We can't talk too much about it because then everything gets complicated and as we are very near to reaching an agreement we don't want to spoil the negotiations."[LNB]West Ham have also been linked with Barrera's team-mate Efrain Juarez, but Trejo says they are yet to receive a bid for him.[LNB]"Juarez? Nothing, nothing official or written, not yet," he added.