Why are you so sure of that. For obvious reasons, he's who I would be rooting for. I think it will be Nickles, Frist, or McConnell. And I don't think Frist wants the job. All he has to do is keep his nose clean the next 6 years and he will be the Republican frontrunner in 2008, assuming Jeb and Cheney don't run. Becoming Majority Leader would be so risky.
In short, he just took one for the team.
It's McConnell or Frist at this point. Normally I'd give the edge to McConnell, but the White House seems to be backing Frist.