LONDON (AFP) - West Indies face an anxious wait over the fitness of fast bowler Fidel Edwards before finalising their side to play in Friday's World Twenty20 semi-final against Sri Lanka here at the Oval. Edwards withdrew with a back problem shortly before the start of their five-wicket win over England at the Oval on Monday that saw them West Indies into the last four. And a West Indies team spokesman told reporters at the Oval here on Thursday: "Fidel Edwards has an irritation in the nerve root of his lower back. He has not been ruled out of the tournament, he is still with us. "He won't be bowling today but we are very optimistic he will be available for tomorrow's (Friday's) match." West Indies captain Chris Gayle said of Edwards: "He has been good for us throughout the tournament. Fidel is the sort of bowler who can win you games and pick up crucial wickets at crucial times even though sometimes he can go for runs. "He is actually a wicket-taker and can change a game for us. He was missed the last game even though we won. He is a key factor for us." Edwards has taken six wickets in four matches at this tournament at an average of 21.50. All-rounder Darren Sammy, who came in for Edwards against England, would appear to be the leading candidate to step into the side if the 27-year-old Barbados quick is ruled out. Whoever triumphs in Friday's match will face the winners of Thursday's first semi-final between Pakistan and South Africa in Sunday's final at Lord's.