Mayor de Blasio's anticipated endorsement of Hillary Clinton is hardly a surprise. But, the expected timing of it is curious, and a sign that the Mayor is trying to find a way out of the box he seemed to put himself in when he refused to support her campaign early on as NY1's Grace Rauh reports.

When news broke this week that Hillary Clinton's campaign was talking to Mayor de Blasio about an endorsement, few were shocked to hear de Blasio planned to back his former boss. It always seemed a foregone conclusion. 

The timing, though, is hardly ideal for the mayor. There does not appear to be a recent speech or policy announcement he can point to and argue Clinton convinced him to come on board now.

The biggest change is that Clinton has hit her stride in the last two weeks. She shined in the Democratic debate and won praise for how she handled the Benghazi hearing.

On Tuesday, the mayor appeared annoyed when asked about the endorsement.

"Don’t reference third party reports," deBlasio said. "When we have something to say on the political front, we’ll say it. I haven’t said anything. And that’ll be something we address in the future.

You can be sure this is not the way de Blasio envisioned his endorsement of Clinton playing out when he held off on backing her earlier this year. Instead, he was trying to position himself as a national progressive kingmaker — even organizing a presidential forum on income inequality that he hoped would drive debate among the candidates.

That forum is supposed to take place in Iowa in December, but Clinton sources say she has not been planning to attend. Her absence would have made it hard for the mayor to justify endorsing a candidate who skipped his event.

City Comptroller Scott Stringer says it is time for Democrats to rally around Clinton.

"We need to unite around her," Stringer said. "I don't think down the line we are going to judge Bill de Blasio based on his political endorsements. We are going to judge him based on issues related to homelessness, working to solve the problems at NYCHA, making sure that we continue to see reductions in crime."

But first, de Blasio has a presidential forum to deal with. And with his anticipated endorsement of Clinton out in the open it may be harder than ever to convince other candidates to join him in Iowa.