The runners and riders to replace Lisa Wilkinson on the TODAY show

Following Lisa Wilkinson's shock departure from the TODAY show on Monday night, speculation is rife over who will be her replacement in 2018.

While Deb Knight fills in until Lisa's successor is named, Nine news readers Georgie Gardner and Sylvia Jeffreys are being suggested as strong contenders to co-host alongside Karl Stefanovic.

Georgie was TODAY's newsreader for seven years before she resigned in 2014 to take on a broader role within the network. Sylvia, who is Karl's sister-in-law, joined the show as a news presenter mid-2014.

Another contender is Nine Network's Rebecca Maddern, who currently hosts The AFL Footy Show, and this year hosted Ninja Warrior alongside Ben Fordham.

Lisa's TODAY show predecessors include Jessica Rowe, Tracy Grimshaw, and Liz Hayes.

On Monday morning, entertainment reporter Peter Ford told KIIS 1065's Kyle and Jackie O that market research he had obtained shows Georgie is the audience favourite for the gig.

There have also been some questionable opinions online, including last year's The Bachelor villain Keira Maguire, and 60 Minutes reporter Peter Stefanovic which would mean he would be joining his brother Karl, and wife Sylvia on the brekkie show.

Last night, Nine revealed Lisa and the network announced they would be parting ways.

"We express our gratitude to Lisa for her 10 years with the TODAY show and are disappointed we find ourselves in this position," the statement read.

"Nine will be going in another direction and will be considering our options in the coming weeks and months."

Meanwhile, Lisa will be joining Network Ten's The Project from early next year.

In a statement released by the Ten, it was announced Lisa will be taking on a "senior hosting and editorial role" with the network from January.

"Lisa will join the team of Ten's award-winning news and current affairs program, The Project, in a hosting role," the broadcaster said.