Originally posted by cmsMaster
... 3.a3 d5 (certainly seems to be the critical defense) - here's a line I think would be possible that I came up with:
4.e3 Be7 5.Nf3 O-O 6.Be3 dxc4 7.Bxc4 Nc6 8.O-O which seems fine for white,...
Perhaps you could play 3. a3 and I doubt you'd necessarily come out of the opening worse but I don't see you getting an advantage either.
In your line 7. ... Nc6 is not a good move. Black invariably wants to play ... c5 in these positions and that looks much better than developing the knight here.
I'd say you're just a tempo down on an already slow version of the QGD.
Having said that, 6. Nc3 instead of 6. Bd3 transposes to a known position (although it's also known to be entirely equal).
Also, Black could try to play more dynamically with 3. ... c5 instead of 3. ... d5 (aiming for a Benoni structure where a3 is unlikely to be useful for White).
If you REALLY want to avoid the Nimzo you could try 3. g3.
Otherwise play 3. a3 if you want to ... just don't expect an opening advantage.