The Spice Girls singer appeared in the latest series' launch episode as a guest judge, before Nicole Scherzinger signed up full time.
© ITV
However, she was allegedly the first choice as the fourth permanent judge, but had commitments with the Australian version of the show, reports The Sun.
A source claimed: "Mel was our first choice. She was so quick and honest. You can't let everyone down gently or the praise is meaningless.
"There's a lot of money on the table for her next year."
Gary Barlow said that he wanted Mel B as a permanent judge back in June.
Sharon Osbourne has also spoken of her interest in rejoining the series as a judge.
The X Factor returns on Saturday, August 25 at 7.45pm on ITV1.
