Wont take Nadal out of the French Open picture yet...Will wait to see how Nadal fares in Indian Wells first.
Also if he is available for Davis Cup before that.
As of chance of Federer winning French or not is not dependent on whether Rafa is fit or unfit, In my opinion its more dependent on the Fedrer's own form.
I think Federer whould win. He is not playing his best, but there is no one else who is playing too good. I have a feeling that this year will be a "Lost year" in Men's tennis as I do not see any great rivalry coming up. Neither do I see many hard fought high class matches.
Of course, if Nadal and others like Djokovic, Murray and Davedenko come up, it will be great, but I think that will be more like 2011.