The midfielder impressed for the Swans in the Championship last term, and was one of the first names in the starting eleven for them.
Downes’ exploits on the pitch saw him draw the admiring glances of several Premier League clubs with Crystal Palace and West Ham keen on snapping him up.
Swansea need to balance the books and they became open to selling Downes this summer with the player being not short of suitors.
Although the Eagles made an offer for the 23-year-old, the Hammers won the race for his signature and are now on the verge of completing a deal for him.
Downes is being put through his medical paces ahead of a move to the London Stadium and he is in the second part of the procedures to prove his fitness.
West Ham are set to wrap up a deal for Downes for a fee believed to be in the £12m range, which is the amount Swansea have been seeking.
The Irons have already snapped up centre-back Nayef Aguerd and signed Alphonse Areola on a permanent basis, and are confident they can add Downes’ name to the list of new signings soon.
