Nice work, srp. It sure does seem like the Suns can no longer rely on Nash to play superhero night in, night out (nor do they need to now with Shaq in the house and Amare doing his best MVP impersonation). A few unproven theories, in no particular order, on why this may be:

1. He's nursing a lingering injury in his shoulder/back/hamstrings/whatever like you suggested. (Time to give Rick Celebrini a call?)
   
2. He's taking a mid-season, in-flight "break" to be fresher for the playoffs, and is struggling a bit because it's just not in his nature to go anything less than all out, all the time.
   
3. He's finally playing like a 30-year-old instead of a man who stepped back in time 10 years. (He still plays much younger than his age, though).
   
4. We underestimated how much the presence of Shawn Marion improved Nash's numbers (although as you pointed out, the "decline" started even before the trade).
   
5. Other teams have finally figured out how to play Nash to shut off his penetration, step into passing lanes, etc. (It only took three years).
   
6. He's subtly trying to move out of the limelight a little so Amare can move toward center stage, maybe as a partial result of any or all of the above. Again, since not going all out, all the time is not his style, it's not an easy transition to make. (Kind of like the kid with a genius IQ trying to "play dumb" in order to fit in).
   

My guess is that we're probably seeing the very first signs of a decline that by all medical standards really should have started a long time ago. But Nash at 80% is still better than just about any point guard in the NBA not named Chris Paul. I also think the arrival of Shaq, Grant Hill, and the new emergence of Amare makes this much less of a problem than it would have been even a year ago. This team doesn't need "superhero Nash" every night. It just needs the version who can push the tempo, and throw the ball into the post when the whole pick and probe thing isn't working. I think Nash will still be a very good point guard in this league for a long time. When he finally hangs it up, it will be on his terms, and most likely the Hall of Fame will be calling. But here's something that got lost in all the other reasons I've spouted off for not being gung-ho about the Shaq trade: I sure did want to see a pint-sized underdog type lead this team to a championship without needing a 7'0" big guy to come in and save the day. I'm still a little disappointed that it isn't going to happen that way.

I agree about the passes.  The pass to Stoudemire at the end or the Hornets game was low, and actually bounced off Amare's calf.  Amare has great hands, and saved Steve a turnover, and was even able to get a shot up (which was missed due to a blocking foul).  If that pass is on target, we are tied or ahead with a three point play with 3.6 seconds left, instead of being behind by one and having to foul.

The passes are just enough off to alter the play slightly.  I felt in the LA game that many of the Laker deflections were due to sloppy passes that would have been layups or dunks if on tatget.

But I think you have to remember Nash was playing pretty stupid good at the beginning of this year.

Before the 15 game selection you bring up Nash was averaging a ridiculous 12.4 assists and 3.6 TOs, putting him at a 3.35 to 1 A/TO ratio. That would easily be his best since 04-05 when he had a 3.48 ratio. Two years ago he had a 3.0 to 1 ratio and last year a 3.05 to 1.

So in the past 15 games, when Steve has averaged a weak 10 assists and 4.5 TOs (2.2 to 1), you could almost see it as a leveling out of what would be his most efficient statistics since 04-05. I mean, that is what statistical history should indicate to us. Nash typically plays right around 3 to 1, so him playing at 3.35 to 1 was bound to come down to where he is now (2.95 to 1). Of course, these last 27 games are going to be strange sample with Shaq in the mix, so who knows where he'll end up.

Last, I think it's worth noting that most of Nash's really bad games over the past 15 have been against good teams.

Golden State - (12A/7TO) They create the most steals in the league and give Nash fits.

New Orleans - (12A/10TO) Chris Paul is a better overall player than Nash (though maybe not better at running an offense), especially on D. Sucks but it's true.

San Antonio - (8A/3TO and 6-18 shooting) Bowen is a lousy bastard.

Cleveland - (9A/7TO) They're flawed overall, but defensively Cleveland is one the best teams in the league.

Boston - (5A/5TOs) Boston plays great D and who knows how Steve's stats are going to look in this new Shaqled world.

Then, of course, there's still a couple of games that were just inexplicably bad (Chicago and Charlotte). Maybe those are indicative of decline or injury.

But, overall, I don't think we should look too much into these numbers. There's no doubt Steve is getting older, but the Suns, in general, are changing and, to be fair to Steve, for the year he's playing at about his average anyway.

And, most of all, it's only the late April to June numbers that really matter.

Another thing worth considering, is that Mavs fans were saying the same things about Steve's supposed declining abilities when he was in Dallas, although nobody here was able to state it as eloquently and comprehensively as our SRP.