Elon Musk will receive an MRI of his neck and upper back on Monday and may require surgery, the 52-year-old said in a post on his X platform, formerly known as Twitter.

The world’s richest person said he will know this week whether surgery will be required, ahead of his proposed cage fight with Meta Platforms co-founder Mark Zuckerberg. He previously said he “might need an operation to strengthen the titanium plate holding my C5/C6 vertebrae together.”

As CEO of Tesla and Space Exploration Technologies, as well as the owner of a closely watched social-media platform, Musk’s health is of intense interest to people around the world. Musk, a notorious workaholic, has said that he has suffered from “mega back pain” after a bout with a sumo wrestler.

The post about the sumo match was accompanied by another with a photo of what appears to be a makeshift ring for the Japanese sport. Musk mentioned the injury last year after challenging Russian President Vladimir Putin to “single combat” over Ukraine.

Musk, who delights in stirring up online spectacles, has been talking up the yet-to-happen fight with Zuckerberg for weeks. Competition between the two CEOs has intensified after Facebook-parent Meta released a rival social network, Threads, that directly competes with Musk’s X.

Zuckerberg posted Sunday on Threads that he suggested Aug. 26 for the match and he is still awaiting confirmation. “I’m ready today,” he said. “Not holding my breath.”