West Indies' seven-wicket defeat last night means that they cannot move ahead of Sri Lanka (86 points) by September 30, the cut off mark for direct entry.
The Caribbean side (78 points in the ODI Team Rankings) can still qualify for the World Cup by finishing in the top two of next year's World Cup Qualifier, an ICC release said.
Sri Lanka, the 1996 champions, join hosts England, India, Australia, Bangladesh, New Zealand, Pakistan and South Africa for the ICC's showpiece event.
"ICC events have always brought out the magic in Sri Lanka cricket, and I look forward to proving that once again. We have a clear plan toward the World Cup, and we will work hard at achieving each step."
The West Indies will now progress to the 10-team Qualifier, where they will be joined by the bottom three sides in ODI Rankings - Afghanistan, Zimbabwe and Ireland - as well as the top four sides from the ICC World Cricket League Championship and the top two sides from the ICC World Cricket League Division 2.