It emerged on Wednesday that Premier League newcomers West Brom have had an initial offer of £12m accepted by West Ham for Diangana.
The Hammers are claimed to be in line to earn as much as £18m from selling the winger to their league rivals.
However, the Baggies still have some more work to do before they can claim Diangana to be theirs as Aston Villa and Fulham are interested in the youngster.
The Premier League duo could still serve a blow to West Brom and scupper their deal with West Ham for Diangana.
Aston Villa and Fulham are in talks with the Hammers in an attempt to reach an agreement for the signature of the 22-year-old.
Dutch Eredivisie outfit Ajax are only keen on taking Diangana to the Netherlands, but would have to sell players first before making a move for the West Ham star.
If any of his suitors manage to strike a deal with West Ham, it would be then down to Diangana to choose his next destination when he discusses personal terms.
