Although Green still has to complete a medical and agree personal terms the two clubs have agreed a deal that could be as much as £2 million.
Green is currently recovering from a groin injury sustained during the England B international against Belarus in back in May but has been suited by a number of Premiership clubs recently. Both Man City and Charlton are said to be interested in Green but he is likely to prefer a move to The Hammers with European football on offer in East London this season.