Thomas has an ankle injury and Long has a digestive problem. Transfer deadline day signings Keith Andrews and Liam Ridgewell were not signed in time for tonight's fixture and are ineligible.
In more positive news, Zoltan Gera has announced that he may be back in action before the end of the season - he was ruled out for the rest of the campaign back in November after rupturing the anterior cruciate ligament in his left knee.
Despite languishing in 15th place in the Barclays Premier League table, the Baggies go into the match against one of Roy Hodgson's former teams in decent form having won three of their last four league games on the road.
However, Craven Cottage hasn't been a happy hunting ground recently for the Baggies. In the last five Premier League visits they have scored only once, and in that match they were thrashed 6-1.