After consultation with his team and medical specialists, Andy has reluctantly withdrawn from the French Open and will instead focus on preparation for the grass court season.
Andy commented “It’s a really tough decision and I love playing in Paris, but after seeking medical advice, I am not fit to compete. Apologies to the organisers and thanks to everyone for the messages of support. Now my complete focus is on getting back on the court as soon as possible”
source : http://www.andymurray.com/news-and-blog/injury-update/
So Roger will be seeded 2 and Rafa will be seeded 3. Possible semis would be, Novak vs Ferrer and Rafa vs Roger, provided the draw will feature 2 and 3 seeds in same half.