For clues about who might be next to get a show on MSNBC, viewers need not have looked further than “Countdown” earlier this month. For eight nights beginning just before the Fourth of July, Rachel Maddow, the host of a program on Air America, the liberal talk-radio network, served as a substitute for the vacationing Keith Olbermann.

“At some point, I don’t know when, she should have a show,” said Phil Griffin, hours before he was promoted on Wednesday to president of MSNBC. “She’s on the short list. It’s a very short list. She’s at the top.”

At the moment every slot at night on MSNBC is taken, with David Gregory at 6 handing off to Chris Matthews at 7, and with Dan Abrams at 9 following Mr. Olbermann at 8. But some shuffling could be in the offing; Mr. Matthews’s contract, for example, is up next year.

For her part, Ms. Maddow, who has been a ubiquitous presence as a political analyst on MSNBC this campaign season, said she is ready whenever the call should come. To hasten that process, she recently hired Mr. Olbermann’s agent, Jean Sage.