There is also the move 13.Bg5, which makes more sense now that:
1) White still has the possibility to play Nc3, and
2) the c-file is open, so that Black might have to move the queen again in response to a quick Rc1.
However, if Black just replies 13...Bb7, then point 1 looks unimpressive, and point 2 does not look that dangerous. So it seems to me that this move order is no problem for Black.

Quote:


According to my database, White responds with 12.Nbd2 in between 80-90% of the games, while after 11...cxd4 12.cxd4 Qc7, White tries something else in almost 50% of the games. So the probability that Black will face something different from the main line is larger with the latter move order. This could be another reason why the 11...cxd4 move order is less usual. That said, though, it is probably simpler to learn how to face White's other tries against 11...cxd4 than to learn how to face 11...Qc7 12.d5, since the character of the position is rather different there.

GMTonyKosten wrote on 08/14/10 at 12:45:54:

maybe white can try to transpose to the 11.d4 Qc7 12.Nbd2 cxd4 13.cxd4 Bb7 14.d5 line (which may not be what black intended to play) by playing Ne2-Ng3, for example 11.d4 cxd4 12.cxd4 Qc7 13.Nc3 Bb7 14.d5 Rac8 15.Bd3 Nd7 16.Ne2 f5 17.Ng3

so if black wants to play 11.d4 Qc7 12.Nbd2 cxd4 13.cxd4 Nc6 or 13...Bd7, then the moveorder with 11...cxd4 makes no sense because after 13.Nc3 Nc6 there is the immediate 14.Be3 (in the mainline white plays Nb3-d2 to achieve this) and after 13.Nc3 Bd7 there is 14.Bg5 (or 14.Nd5)

I am not a big fan of learning all the mainline theory, so I have decided to play 11...Qc7 12.d5 which might be more effective against club players. However, if what you are saying is right then black can completely avoid this. If that's the case I wonder why not more players use this move order to cut down on the lines they have to be prepared against since as far as I know 12.d5 is not considered ?!

How does white prove this move order inprecise? 13.Nc3 would directly take advantage of the fact that white has no pawn on c3 anymore, but I cannot tell if this is better than 13.Nbd2 which would be the mainline.