Here's some statistical comparison:
StDev Player
5.369509536 Batum
5.609612741 Ibaka
6.075118987 Parsons
7.227844889 Deng
7.235938363 Hayward
7.237800352 Thad Young
7.60783699 Jeff Green
Jeff Green is the most inconsistent.
Small forwards who are closest to Green in ppg are Ariza, Josh Smith, PP, Nick Young, Evan Turner and Chandler Parsons. I'd guess there' more inconsistency in that group.
Things I would look at besides the simple ppg stdev, would be USG%, touches and minutes.
Unless players are being comparably used, in a similarly consistent basis, arguing over whether the players are consistently performing seems silly.
I also think it is absurd that anyone is looking for 'consistency' from any player on the Celtics over the last season and a half.
The only thing constant about this team has been ridiculously frequent and often dramatic change.
Last year was year of constant major changes, with Green starting the year coming back from a giant rehab, Avery missing, then coming back only in time for Rondo & Sully to be lost for the year and the roster to be rounded out by refugees from the China league. Ironically, the roster, however flawed, was finally 'stable' over the last couple of months of the season. Green seemed pretty consistent to me during that stretch, but again that depends on how you want to define 'consistent'.
This year, after trading away two of our best players and overhauling the roster with youth, we've had adventures at "point guard". Green has played a little under 1700 minutes so far this season. Only about 62 of those minutes have been with Rondo (who is coming back from a giant rehab). The rest have mostly been with Bradley or Crawford at point. Wheee! What a fun ride that has been! We've also had a constantly changing front-court as Stevens has shuffled between different combinations of our PFs.
I'm sorry, but fans expecting 'consistency' (whatever that means) in any player through all that are simply, imho, not really paying attention.