Riotbeard said:
Is he declining (as in has played consistently better, and will never get back to his absolute peak in terms of consistency and quality)? In my opinion, yes. Doesn't mean isn't still insanely good and very close to his highest level, but if careers and athletic physicality have a peak and then some sort of decline from that, then he if definitely not as good as his absolute best years, and I don't see him having another 2010 or even quite 2013 again. 2 out of 3 majors competed in and 5 masters won't happen again, IMO. He could still win two majors in one year though although next year would be his last really good shot at it.
He could still win 2 majors THIS year, and yes, probably next year would be his last to do it. El Dude gives us statistics for when players peak, plateau and decline. Statistically, Nadal should be in plateau years. Which implies no more than flashes of the former brilliance, but a solid level, and still capable of beating anyone. Which is what we saw, essentially, from Federer at 28. So the diminishment of results seems not surprising, but anyone who thinks he's in a
steep decline, (yes, I'm looking at you, isabelle,) is probably fooling themselves.