Here's Who Is Rumored To Be Replacing David Letterman

David Letterman just announced he's retiring next year and the rumor mill is already buzzing over who will replace him at the "Late Show."

As of now, there are four main names being tossed around: Craig Ferguson, Stephen Colbert, Conan O'Brien, and Chelsea Handler. Let's see how they stack up.

1. Craig Ferguson

Longtime "Late Late Show" host Craig Ferguson - whose 12:35am CBS show immediately follows Letterman's - reportedly has right of first refusal in his contract for the "Late Show" gig. However, CBS may have the option to buy him out and hire a different host.

Here's how The New York Times' Bill Carter described it:

[Ferguson's] previous contracts with CBS have included what amounts to a "Prince of Wales" clause, giving Mr. Ferguson the right to inherit the late-night show in the 11:35 p.m. time period should Mr. Letterman decide to leave. (Those clauses have never been ironclad, however, because a network can choose to pay off the deal rather than complete the succession, as Mr. Letterman learned when Mr. Leno was chosen to succeed Mr. Carson in 1992.)

"Ferguson's CBS contract also expires in 2015, so if CBS opts to buy him out instead of giving him the prestigious 'Late Show,' he could end up leaving the network altogether, leaving the network's 12:35 slot vacant, as well," reports Splitsider.

But considering "The Late Late Show" is produced by Letterman's Worldwide Pants company, it could be an ideal transition.

2. Stephen Colbert

Entertainment blogger Nikki Finke apparently has sources who say Stephen Colbert is "the only one on the air currently that CBS is considering."

The report doesn't sound too outlandish, as Colbert's contract with Comedy Central is up at the end of 2014 - making Letterman's 2015 exit ideal timing.

3. Conan O' Brien

In 1993, Conan O'Brien succeed eed David Letterman on NBC's "Late Night" and it worked out well, so why not try again?

After spending the last four years on TBS following an embarrassing firing at NBC's "Tonight Show" in 2010, we're sure Conan would like to take revenge while sitting at Letterman's CBS desk.

The timing could be a bit tricky with Conan's TBS contract not being up until November 2015, but so far Letterman has only said he will leave "sometime in the not too distant future - 2015 for the love of god." So there's still plenty of time to figure out the exact details.

4. Chelsea Handler

It is ironic timing that Chelsea Handler announced earlier this week that she is leaving the E! network but already has seven mysterious "suitors lined up."

The "Chelsea Lately" host will leave E! when her contract expires at the end of 2014, which would make for perfect "Late Show" takeover timing.

One fan who thinks it could actually happen? Chris Rock, who posted the news of Letterman's retirement on his private Facebook account, with his bet for a replacement.

Ironically, Letterman's replacement was the plot line of a three-part "Louie" arc which placed Chris Rock, Jerry Seinfeld (do it, Jerry!), and Louis C.K. himself as the top contenders.

Other candidates whose contracts are up in 2015? Jimmy Kimmel and Jon Stewart, but both seem unlikely to quit their day jobs any time soon.

Even Neil Patrick Harris' name is being thrown into the ring. With his hit CBS show "How I Met Your Mother" just ending this week and already having proven he can host live Emmy Awards shows for the network - the timing may be right.

Let the games begin!