Revealing her decision to leave Discovery after three years, Root said she wanted to pursue other opportunities in media in the UK.
Root said: "After much consultation with friends and family, I have decided that this is the best time for me to leave Discovery and return to the United Kingdom to pursue other opportunities in the media industry."
A BBC spokesperson said the recruitment process was confidential and the corporation would not comment on speculation.
The theory that Root is returning to the corporation is supported by a claim by US entertainment trade journal Hollywood Reporter that BBC director-general Mark Thompson visited the US two weeks ago.
A succession of big names have ruled themselves out of the frame for the job during the BBC's search, including BBC Two controller Roly Keating and Channel 4's director of television Kevin Lygo.
It has now been eight weeks since Peter Fincham resigned on the day a report into the 'Queengate' affair criticised the adequacy of his response to the media storm about the controversial programme trailer. The first part of the programme, now called 'Monarchy: The Royal Family at Work', finally aired this week and pulled in 6.7m viewers.
At Discovery, Root's role of president and general manager of the Discovery Channel and the Science Channel has been taken up by John Ford. Ford was previously the head of Discovery Times and Military Channel.
David Zaslav, president and CEO of Discovery Communications, commended Root on doing a "great job".
Root was BBC Two controller between 1999 and 2004, when she was succeeded by Keating.
While under her reign, BBC Two was awarded channel of the year at the Guardian International Media Festival.
This article was first published on brandrepublic.com