Mark Zuckerberg Tears ACL Sparring MMA, Undergoes Surgery To Repair

This never happened coding ... Mark Zuckerberg tore his ACL training MMA, and was forced to go under the knife, delaying a real deal fight Zuck had scheduled for early next year!

The Facebook founder shared several photos from his hospital bed Friday afternoon ... announcing he's suffered a serious injury to his left leg.

"Tore my ACL sparring and just got out of surgery to replace it. Grateful for the doctors and team taking care of me. I was training for a competitive MMA fight early next year, but now that's delayed a bit. Still looking forward to doing it after I recover. Thanks to everyone for the love and support," 39-year-old Zuck wrote on Instagram.

The bit about the upcoming fight is news, too. No one ever publicly announced Mark scheduled a mixed martial arts bout.

A bunch of MMA stars wished Zuck well after hearing about his injury, including former UFC champ-champ Henry Cejudo, who wrote ...  "Speedy recovery Mark! 🙏"

Through training, Zuckerberg has befriended many of the world's top fighters like Israel Adesanya and Alex Volkanovski.

FYI, the ACL, or the anterior cruciate ligament, is a band of tissue that connects your thigh and shinbones together and is a common injury among athletes.

Of course, Zuckerberg and Elon Musk spent months negotiating terms for an MMA fight, though it never came to fruition. The billionaires blamed each other for the breakdown.

Earlier this week Musk went on Joe Rogan's podcast and again reiterated that he would fight Zuckerberg "anytime, anywhere, any place."

ACL recovery typically takes around 9 months, give or take, to return to competition post-surgery.

Until then, Mark's likely not fighting anyone.