Baggies boss Roy Hodgson was forced to turn his attentions to Green after being priced out of a move for Birmingham's Ben Foster.
Newcastle are also interested in the West Ham stopper, but Green is believed to favour a move to the Hawthorns.
Making their move: Green (left) and Long are wanted by West Bromwich Albion
Reading striker Long, who scored 25 goals last season, has one year to run on his current deal.
The Championship club have slapped a ?10million price-tag on the Republic of Ireland hitman, but West Brom are hopeful of negotiating a reduced fee.
Everton, Sunderland and Newcastle are all monitoring the situation.
West Brom pull out of Long deal as Reading slap ?10m price tag on in-demand striker Reading demand ?10m for Long as Everton, Sunderland and Toon circleSteve Bruce sets his sights on ?7m Long shot to pip Newcastle to Reading striker