This is according to the LoHud Yankees Blog:

Jorge Posada just revealed that Joe Girardi told him on Sunday that Jose Molina will catch A.J. Burnett in this series.

...

“I just hope we win that game,” Posada said. “That’s all I’ve got to say.”

He added, “It’s not like I didn’t see it coming.”

When asked if he might be the DH when Molina catches, Posada said he wasn’t sure but that, “Matsui is our DH.”

Also confirmed on Tyler Kepner's twitter page.

Hopefully this works out for everyone. With AJ pitching to a comfortable backstop, there will be no excuses. I just hate to have Matsui's or Jorge's bat sitting on the bench in favor of Jose Molina.