The 60-year-old star is said to have suffered numerous fractures in his horror accident in Malibu, California last month.
The music guru was taken to hospital where he had emergency surgery and he is now resting at home with family.
Fellow Britain's Got Talent judge Amanda has told how when she heard the news she feared the worst.
She told The Sun: "I honestly panicked it could be fatal. It was gut-wrenching. I got a text in the night. I couldn’t sleep after.
"I felt physically sick as I didn’t know how bad it was.
"I wanted him to be alive, but I also wanted him to be able to walk as he’s such a good friend."
Amanda is unable to keep direct contact with Simon as he doesn't use a mobile phone but is getting updates on his wellbeing from his girlfriend Lauren Silverman.
She told how she sent the BGT head honcho Lego, cashmere socks, books, butterscotch and his favourite food Angel Delight.
"Lauren is keeping his spirits up and cooking turkey shepherd’s pies", Amanda said.
She also revealed how "a producer spoke to Simon" and says he "sounds amazing" and "really well".
On the same day as his accident, Simon had an emergency operation on his back, which took six hours and involved having a metal rod placed in it.
The doctors told the TV mogul that he was “very lucky” not to have suffered paralysing injuries.
It is thought that Simon will not be able to return to the panel in time for the final which will air in October.
But Amanda added she thought he could record a segment for the final or appear via a Zoom