Caroline Thomson, the BBC's chief operating officer, is being tipped to become the first female director general at the corporation.
She is second favourite to succeed Mark Thompson in the role, according to bookmaker Paddy Power.
George Entwistle - director of BBC Vision - has emerged as the early favourite to take on the top job at the BBC when it becomes vacant.
Speculation has been prompted by the corporation appointing a firm of international headhunters to produce a "succession plan" for the position.
Thompson, 54, has been in the role since 2004, taking over after the departure of Greg Dyke.
BBC Trust chairman Lord Patten revealed earlier this week that a firm had been appointed. The company, Egon Zehnder, will draw up a plan by Easter.
Some reports have suggested Thompson may leave after the London Olympics this summer, but it is not clear how long he intends to continue in the role.
A BBC spokesman said: "Whilst speculation is inevitable, as the BBC chairman has made clear earlier this week, this is sensible succession planning and does not signal an immediate vacancy."
The director general (DG) role has a salary of £671,000 but Lord Patten has said the position will offer less in future.
Ms Thomson has been chief operating officer since 2006 and, following the departure of Mark Byford, also deputises for the DG.
She began her broadcasting career more than 30 years ago as a BBC journalism trainee.
Paddy Power has given odds of 2-1 for her to become the next director general, with Mr Entwistle at 7-4.
Another female contender is director of news Helen Boaden at 9-2.