Federer played all but one of the Masters 1000 events in 2009, and while he took home two titles in his two finals, he lost in the semifinals of three (Indian Wells, Miami, Rome) and before the semis in Monte Carlo, Canada and Paris. Add to that finals losses at the Australian Open, US Open and Basel and we see a portrait of a player who is typically in contention on the final weekend of an event, but who is no longer the lock he was in previous years to walk away as the last man standing.
If Rafael Nadal can return to full health and form (not small "ifs"), Federer will be hard pressed to maintain the #1 ranking for 2010. Nadal caught and passed him in 2008, and was pulling away at the beginning of 2009. Federer's ascent back to the top spot was directly tied to Nadal's inability to defend any of the points from his 2008 Wimbledon title, and his never returning to full form after his post-Roland Garros layoff.
Tell me if you disagree.
