It can be easily confirmed here that the new list of main speakers doesn't show his name anymore:
...This post by Costa however has the old list, which showed his name:
James Powell (University of California, Berkeley)
Matthew Rabin (University of California Berkeley)
Rohini Pande (Harvard U)
Edward Prescott (Arizona State U and FED Minneapolis)
Matthew Rabin (UC Berkeley)
Well, it's clear that, whatever may be the reason, he'll not attend the conference anymore.