http://www.floridatoday.com/!NEWSROOM/spacestoryN1212OKEEFENU0.htm

From the bottom of the Florida Today article a list of possible replacements:

It now appears that return to flight will happen under a new administrator's watch.

Among the other candidates, Sega is perhaps next closest to the White House staffers advising the president. The former shuttle astronaut is serving as a director of research and engineering for Pentagon and was involved in drafting Bush's moon-Mars policy.

Crippen, retired and living in Florida, piloted Columbia on the first shuttle mission in 1981 and once was director of the Kennedy Space Center.

Bolden also recently served on a National Academy of Sciences panel that recommended reversing O'Keefe's January decision to cancel a shuttle repair mission to the Hubble Space Telescope. Without O'Keefe's opposition, the shuttle mission to Hubble would be easier to reinstate.

Walker retired in 1997 after two decades in the House of Representatives, where he had become one of Congress' leading experts on aerospace and space exploration.