In January, 2K Sports shocked sports video gaming with the announcement that it would, in fact, make Major League Baseball 2K13 this year. The label's prior license with MLB expired at the end of 2012, and no one expected it to be renewed. Of course, it's not like any other publisher was building an MLB-licensed video game in the meantime, which left the National Pastime in the awkward position of not releasing at all on the Xbox 360 this year.
So everyone assumed the two sides re-upped just to plant the flag one last year on this console generation and move on, and given the lack of marketing communication I have seen about MLB 2K13, that would seem to be a correct appraisal. All of one (1) screenshot for the upcoming game exists, and from the description of the feature set it sounds like you'll be getting an updated roster, the Houston Astros in a new division, and little else. I'll also be very interested to see what soundtrack the game has, if it has any.
What 2K Sports says, or doesn't say, about this game in the runup to its March 5 release will speak to what we may expect from it. And here is, so far, the only hype video for the game. 2K did get the reigning American League Cy Young winner, David Price, but I doubt he cost very much. The game went to the Tampa Bay Rays for a cover star in 2010, coming off the stinging disappointment of MLB 2K9.