The music mogul is reportedly on bed rest in a bid to be well enough for the live shows from Wembley Arena.
The 57-year-old is the only judge not have an act in the final after his last act, Emily Middlemas, was eliminated last week.
An X Factor source told the Daily Star: “He’s on bed rest. He’s doing all he can to get better for the final.”
Simon was a no-show at the ‘X Factor’ press event on Thursday night, which was attended by Sharon Osbourne, Louis Walsh and Nicole Scherzinger.
Not that it mattered, as Louis Walsh managed to provide plenty of headlines today after telling HuffPost UK’s reporter to “fuck off” when he was asked about Cheryl Fernandez-Versini.
He spat: “Simon wouldn’t invite Cheryl back because we have Nicole. We have Nicole and Sharon - we don’t need another girl. So go and fuck off now. No silly questions, seriously.”
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The music manager, who was on the red carpet with his finalists 5 After Midnight, then whacked the microphone that was being used to record the interview.
Cheryl’s boyfriend, Liam Payne has since jumped to the defense of the former Girls Aloud star following Louis Walsh’s comments.
The One Direction star took to Twitter on Friday morning to tell Louis in no uncertain terms what he thought of his comments and behaviour.
“Congratulations Louis Walsh for setting the worst example on handling media for his band who are about to step into a very hard industry,” he tweeted.
“Maybe it’s about time you realise it’s not all about you and shut the f**k up for once, let them speak.”