While Sharon Osbourne, Gary Barlow and Louis Walsh are all expected to sign up for the next 'X Factor', Scherzinger is still not committed because of concern about whether she can do the show while promoting her next album, reported Sun online.
Scherzinger, 34, who has reportedly been offered 1 million pounds to return to the show, did intend to sign up for the 'X Factor' once she has worked out a deal.
"Producers don't want to be left in the lurch... So, Mel is being lined up in case talks fail," a source said.