As others here also noticed, CBS included a promo in the episode aired tonight for pre-orders of TAR 12 and 13 at Amazon.com.
When I checked Amazon tonight, there was nothing listed, so I checked the TVShowsonDVD.com website, and that site had no news items concerning this release pre-order either.
I contacted that website, and made inquiries; one of their editors also noticed that promo tonight on TAR and they've indicated that CBS had done the same thing with a recent release of new Survivor seasons recently, and based on that experience they believe something will show up on Amazon tomorrow (Monday).
I'll check as well, and I do get notifications from TVShowsonDVD concerning TAR when they have news as well.
It's a bit of a sloppy way to do it; but I guess we shouldn't be surprised.