Dennis Miller (search) quit CNBC Wednesday as the network was preparing to dump his low-rated talk show.

Sources say CNBC (search) was going to to axe "Dennis Miller" next month. But Miller apparently hastened the process when he was told of the plans.

CNBC will add a second airing of "Mad Money with Jim Cramer" in the Miller timeslot for the time being.

"I have spoken with Dennis Miller about these plans, and he has let me know that his strong preference is to leave his program immediately," CNBC president Mark Hoffman wrote in an internal memo.

"Dennis Miller" had struggled to find an audience since launching in January 2004. The show is taped in Los Angeles.

Miller was one of several high-profile hires made last year by CNBC in an effort to boost the network's prime-time visibility.

CNBC also gave a weeknight talk show to tennis great John McEnroe. That show also struggled — occasionally generating Nielsen "hash marks" for low viewership before being canned last December after five months.

Miller, who hosted "Dennis Miller Live" on HBO for eight years, joined CNBC after a two-year stint in ABC's "Monday Night Football" booth with Al Michaels and Dan Fouts.

CNBC will continue airing day-old repeats of "Late Night with Conan O'Brien" at 7 p.m. EDT until it debuts a new show. The network declined to provide details on the new show.

"The Big Idea with Donny Deutsch" — hosted by the well-known ad guru — remains at 10 p.m. EDT.

"Dennis is an exceptionally talented comedian with an unmatched wit, and he and his team consistently delivered a very entertaining program," Hoffman wrote in his memo.

Miller's agent did not return a call seeking comment.