Well, it ought to. See Nick Robinson's report HERE.
To be fair to Mr Miliband, it is no different to what he has always said. And he is right that the way Clarke and Co have approached the whole issue has made it very hard for him to enter the race without prolonging the Blair-Brown feud into the next generation and thereby splitting the party.
Cynics will say there's a deal, and that Miliband must have been offered the Foreign Office, or something. Sceptics will say he hasn't uttered the magic words "If nominated I will not accept, if elected I will not serve."
For what it's worth, I think that if he isn't standing, it's probably for the simple reason that he recognises that, at the present time, Gordon will be a better Prime Minister than he would be.