Mayor Bloomberg has used his weekly radio appearance recently to charge the UFT with holding up teacher evaluation talks. Today, he didn’t mention the union at all.

Instead, it was Chancellor Dennis Walcott, who joined Bloomberg on the John Gambling Show, who cast blame on the union and its president, Michael Mulgrew, for blowing Walcott’s self-imposed deadline to make a deal.

“It’s really tough to negotiate when the UFT walks away from the table,” Walcott said. “Mr. Mulgrew has instructed his negotiators that they shouldn’t negotiate with us, at all — they shouldn’t even talk to us on other issues. … That’s tough to really operate from.”

He added, “We don’t have a clue what they want.”

That wasn’t quite true. Alarmed by a spate of reports from teachers about improper observations, Mulgrew did halt evaluation talks this week. But he set a clear condition for them to resume: an agreement on how new evaluations would be rolled out. He invited Walcott to negotiate about implementation, but no talks have yet taken place.

The city and the union are both under pressure to agree on a new evaluation system by Jan. 17 or lose state school aid, a threat Gov. Andrew Cuomo reiterated this week. To give state officials time to review their plan, Walcott had said he wanted to settle with the United Federation of Teachers by Dec. 21 — today.

At stake for the city is about $250 million, a tally that Bloomberg and Walcott have both warned could cause painful budget cuts to schools and other city services. Bloomberg sounded less concerned today, even as he suggested that he is not expecting an agreement.

“We said, if we don’t have it by then, we can still keep negotiating, but we’re going to start assuming in our budget preparations … that we will not have the money,” he said. “Maybe we’ll be pleasantly surprised and have to reverse it. I’d rather we do that than find that we didn’t prepare.”

He and Walcott each left the door open for the city to turn down any deal it is offered. A portion of the broadcast was obscured by a loud electronic sound, but it resumed as Bloomberg said, “We’re not going to sell our students down the road for some money.”

Walcott followed quickly with, “We’re not going to do something just for $250 million.”

Bloomberg gave a clue about what would cause him to favor an evaluation system when Gambling noted that more than 600 districts across the state have submitted teacher evaluation plans to the state already.

“I don’t know whether any of those evaluation plans evaluate and do anything meaningful and I don’t know whether they any of them are operable for us,” Bloomberg said. “We’ve got to worry about us.”

As a bonus, he offered his definition of what makes a good teacher:

“Quality teachers are teachers who know how to maintain discipline in their classroom, know how to deal with the issues facing today’s kids … , know how to deal with kids from families that are very different than they were when I went to school, and know how to deal with new subject matter, and know how to work with other teachers and their managers, the principals – it’s a very complex thing and it’s not a job for everybody.”