Chris Cillizza reports that Evan Bayh is set to endorse Hillary Clinton this afternoon. As Chris points it, Bayh's move is likely to ease him onto the Clinton vice-presidential short-list should she win the nomination.
Probably the most frequent question I get when I talk to friends and family members about the presidential campaign is whether Clinton would choose Obama as her running mate if she were the nominee. To put it simply: This strikes me as completely ludicrous. Obama has many merits, but I don't see the first woman to win a major-party nomination turning around and selecting the first black man to appear on a major-party ticket--particularly a politician as cautious as Hillary. The political pros around her are going to worry that it's too much "change" too quickly, whether or not that would actually be the case.
With Clinton as the nominee, the vice presidential nod would almost certainly go to an inoffensive white male, like Bayh or Tom Vilsack. And so it makes sense for Bayh to make an early play for the spot. (Not as early as Vilsack, who endorsed Hillary months ago, but still pretty early.)
One other thing to note: The same vice-presidential logic applies to Obama--he'd probably also look toward an inoffensive white male as a running mate. So you could argue that Bayh might have made the short list with either candidate, and that his decision to sign on early with Hillary is an important data point about where the nomination is headed. (On the other hand, people like Bayh or Vilsack may be a little too DLC-ish for Obama's taste, so who knows...)