It will not happen this year. If it didn't happen last few years when Federer played much better, it will not happen this year when he plays totally average. Unless he is really saving freshness for clay season.
I agree that the next few weeks will tell everyone if Fed is ready to still contend for the French. Unlike some others who say he doesn't have to do well at Monte Carlo & Rome, I think he HAS to win one of them(vs Nadal) to prove to himself that he can beat Nadal on the type of red clay that is featured at Roland Garros. Of course, even beating Nadal in a best-of-3 at Monte Carlo doesn't mean anything, unless he does it straight sets.