Summary: The announcement is a strong sign that Huckabee will not be running. Huckabee's aides are not aware of his decision; if he were to announce that he is running, he probably would have told his aides first. Moreover, there are complicated legal issues that would arise if Huckabee used his show to announce that he's running. By contrast, there's nothing wrong with using the show to say he's decided not to run.
Analysis: In an earlier post, we saw how a candidate may convincingly decline to run. An announcement of this nature would suffice. After all, the announcement is entirely voluntary, not prompted by an interviewer's question. In the post, we observed that if Huckabee announces he's not running, then he's not running.
If Huckabee declines to run, it will send a tremendous shockwave through the Republican field. Huckabee has been polling well, not just in national primary polls, but also in Iowa and South Carolina polls. Every candidate who has won both Iowa and South Carolina has won the Republican nomination. Huckabee nearly did it last time, and is in a good position to succeed this time.
Huckabee's departure would open the race considerably in Iowa and South Carolina. It might also increase the odds that the winner of New Hampshire could win in South Carolina--or at least, that the winners of Iowa and South Carolina would be different candidates.