The 'Tea and Toast' singer fell ill earlier this week and show bosses made the decision today (October 26) not to include her in the performance lineup.
"NEWS: @lspraggan is just too unwell to perform on tonight's #xfactor," tweeted the official X Factor account, before adding: "Lucy will proceed to next weekend's show as happened with @diana_music [past contestant Diana Vickers]."
Vickers was issued a bye during the fifth week of the 2008 series after suffering with laryngitis. As a result, she was not subjected to the public vote and automatically progressed to the sixth round of the competition.
Spraggan, who is reportedly suffering from "severe flu", was last seen in public on Wednesday night (October 24), when she attended fellow contestant Rylan Clark's Halloween-themed birthday party dressed as a pumpkin.
The 21-year-old from Sheffield has not updated her own Twitter account since before the celebrations. Clark - who along with Spraggan is currently staying in a nearby hotel after being kicked out of the official contestants' lodgings following drunken behaviour - took to his account earlier today and posted an update that read: "F**k I'm ill."
No announcement has yet been made about whether Clark will compete in this evening's live show.
The X Factor continues tonight at 8.20pm on ITV1.
Photo gallery - X Factor stars at Rylan Clark's Halloween birthday party:
Copyright: Rex Features Copetti/Photofab/Rex Features