After searching around the net, I found that this problem is also plaguing some Playstation subscribers to MLB TV. We all paid for a subscription to MLB to the tune of $124.95 and are getting gyped out of watching MLB spring training games.
The latest word on when the 2012 season will start to be available from MLB is some time in early March. Well folks, it is early March and spring traning has begun! Lets get this taken care of! If you want to stay up to date on discussions about the problem, you can check out this Apple Discusison Thread.
If you see any changes on your Apple TV, please do leave a comment here. But please, spare me the "Yankees Suck..." comments. They probably will have a hard time winning the AL East this year anyways...
Now a quick plug on Ubuntu for MLB subscribers. Yes, you can watch MLB games from your MLB account on Ubuntu and Xubuntu. However, the HD and DVR options do not work unless you have a Mac or Windows machine. I was able to watch a MLB game on my Xubuntu 12.04 box without a hitch.