the damage is "bad" casting further doubt on her competing for the Glitterball trophy.
The exact cause of the injury is unknown but it left AJ in excruciating pain.
She said: "I can't pinpoint when it happened during training, in fact we felt really positive after training on Monday, I felt fine. But the pain came on so quickly and acutely, that I actually projectile vomited."
The weight of the situation has played heavily on her mind all week, and there's been lots of tears.
She said: "I'm unable to stand on my right foot and I can't stand up without crutches, and I'm really upset, I'm sorry."
"I'm upset because we were so excited on Monday, we've got three amazing dances that we really, really want to perform. I know I'm upset but I am genuinely remaining hopeful and I'm surrounded by a really great medical team who are trying their best to get me back on my feet."
AJ reached the final after impressing the judges week after week with pro partner Kai Widdrington.
In the semi-final they danced a very sultry rumba to Show Me Heaven by Maria McKee, and fans noted their chemistry was "off the charts".
The pair have refused to confirm or deny if their connection is romantic, but it paid off as they sizzled on the Strictly ballroom floor and made it through to the final.
EastEnders star Rose Ayling-Ellis is the frontrunner tipped to take home the Strictly prize on Saturday night.
Rose is paired up with Giovanni Pernice who branded Rose "the best partner" in a recent interview.
Since appearing on Strictly, the deaf star has continued to wow the judges and now is tipped to scoop the crown.
Chef John Whaite will be dancing alongside pro partner Johannes Radebe in the final.
The TV star shot to fame when he won Bake Off back in 2012.
John and Johannes made Strictly history as the first male same-sex pairing to compete and have done well on the scoreboard each week.
As well as the coveted Glitterball trophy, the Strictly winner scoops a whopping £100,000 to take home with them.
Past Strictly champions have topped up their cash winnings by landing more lucrative TV deals after the show.
The Strictly Come Dancing 2021 final will air on BBC One this Saturday, December 18, 2021.
You can catch the action from 7pm and the result will be announced at the end of the show.
Strictly’s AJ Odudu in tears after horrific injury left her in agony on crutches – with the final in doubt