Felix Leiter may not appear in Bond 23, according to a report in Comingsoon.net., which states:
Wright told ComingSoon.net at the Toronto International Film Festival today that he hasn’t gotten the call to return. With filming starting soon for a November 9, 2012 release, we assume the production would have been in touch with him already.
While Wright’s portrayal of the CIA agent in Casino Royale was among the best we’ve seen, he is very much a subsidiary character and needn’t appear in every film. While his role in Quantum of Solace was very much reduced, at least the character wasn’t wasted in the same way as Rene Mathis.