As reported by BuzzFeed:
Wisconsin Rep. Paul Ryan, the icon of the anti-spending movement in the Republican Party, has communicated to former Senator Rick Santorum that he will endorse Mitt Romney, according to a source familiar with the conversation.
Ryan's staff called Rick Santorum today as a courtesy to announce the news. The announcement from Ryan himself is expected this weekend, most likely during one of the Sunday shows, the source said — and in the run-up to the Republican primary.
I thought he might do it tomorrow morning. I guess Sunday morning makes more sense. We'll have to wait and hear what he says to see if this is an embrace of Romney or, as it was with Rubio, just an embrace of the electoral reality.