If Rafa was Borg-like then he would have retired after 2011, when Novak took him to school all year, more convincingly than McEnroe did Borg in 1981. But then Rafa had a nice bounce-back in the first half of 2012 and one of his best years in 2013.
What we're seeing now, from after Roland Garros 2014 on - about a year - is probably the worst span of Rafa's career, at least going back to when he was a pup in 2004. He is clearly not the Rafa of old. The question, as I see it, is not whether Rafa is in decline, but HOW he is declining and will continue to decline. Every player is different in this regard, although there are some general patterns - what I have called the various phases of development (around 17-21), peak (22-26), plateau (27-31), and decline (32-).
If we look at Roger, we see a slight half-step down in 2008-09 which can't be accounted for solely by Rafa's rise and the emergence of Novak and Andy as Roger's overall win pct against other opponents also declined a bit. I don't have the numbers on me, but I've crunched them before. Then Roger takes another half-step down in 2010 and and then another step down 2013. Each time he dropped a half-step, he was able to right the ship for a couple years or so. 2013 looked like the end was really upon us, but then he had a strong year in 2014. But one thing we've seen is that even though he's been playing at a higher level for the last year and a half, he still is more prone to go out early in Slams now - he's gone out in the first week in two of his last five Slams, going back to the beginning of 2014.
But my point is, Roger has been able to slow his decline and remain at a high level, even over-coming a nearly disastrous 2013. Rafa's 2015 could be similar to Roger's 2013. Actually, despite their almost 5 year age different, Rafa has always been only 2-3 years behind Roger. Roger broke through to the top 10 in 2002, won his first Slam in 2003. Rafa did both in 2005.
One difference between Roger in 2013 and Rafa now, is that this is Rafa's second sub-par year in a row. Certainly 2014 was marred by injury, but his overall performance was also lower than his best years. Actually, if you look at Rafa's career, he seems to have two types of years: great years in which his win% is in the 88-91% range (2005, 2008, 2010, 2013) and merely good years in which it is more in the 81-83% range (2006-07, 2009, 2011-12, 2014) - although 2011 was quite a good year, just marred by Novak's dominance. 2015 is his first year in which he has been below even that range, and he's quite a bit below at 74%, with clay season almost done. Even if he wins Roland Garros and goes 7-0, his overall win % would still be only at 78% at the end of clay season, far from where he needs to be and thus unlikely to surpass 80%.
So it is hard not to think that Rafa is amidst a rapid decline, but I'm not quite ready to count him out. One narrative that I could see as a possibility is that he loses at Roland Garros this year and limps to the finish line this year, then trains like crazy and has one more great clay season next year in 2016, reclaiming RG and several other titles before calling it quits - along with Roger - by year's end. While I'd be sad to see both go, wouldn't it be fitting to see them go out together?
