The experienced centre-back received a late call-up to Mark Hughes' squad after a number of regulars were forced to withdraw because of injury.
Williams completed a full training session with the Welsh squad today, prior to tomorrow's clash which kicks off at 3pm.
The likes of Craig Bellamy, Gareth Taylor, Nathan Blake and even John Hartson look set to miss the game, whilst Cardiff City centre-back Danny Gabbidon could also have to sit the game out because of a back injury.
James Thomas of strugglign Swansea City was another player to receive a call-up, he will join Robert Earnshaw and Neil Roberts as Wales' only fit centre-forwards.
If he gets on Williams will hope to help his nation achieve another victory as they attempt to qualify for Euro 2004. They already have two victories under their belts having defeated Finland and Italy.