Sky Sports sources understand that West Ham are set to announce the signing of Mexico international Pablo Barrera on Friday afternoon.
New Hammers manager Avram Grant told Sky Sports News on Thursday that the winger was set to arrive at Upton Park if a work permit was secured.
It is now understood that the East London club have gained the neccesary paperwork and Barrera is ready to sign a four-year contract in a £4million switch from UNAM Pumas.
The 23-year-old impressed at this summer's World Cup finals when used as an impact substitute and he could prove a potent weapon in the Premier League.
West Ham announced on Wednesday that they "should be in a position to unveil at least one exciting new signing on Friday".
It would therefore appear that Barrera is the player in question, while skysports.com understands that Lyon striker Frederic Piquionne is undergoing a medical with West Ham on Friday.