Belal Muhammad's first defense of his UFC welterweight world title will have to wait ... as the champ has been forced out of his main event fight at UFC 310 after suffering a nasty bone infection.
The 36-year-old revealed the news Tuesday morning ... showing off the ailment before going under the knife, and we're not doctors, but it's safe to say a human toe probably shouldn't be that swollen!
"Caught a bone infection in my foot .. had to put a picc line in my arm for iv antibiotics the next 6 weeks with no physical activity," Belal said.
BM apologized to fans who were planning to make the trip out to Las Vegas for his fight, promising to be back soon.
Muhammad won the title in July after defeating then reigning champion, Leon Edwards. Belal, in Leon's home country of England, won by unanimous decision ... after arguing for years he was worthy of a title shot.
Muhammad was set to take on undefeated challenger Shavkat Rakhmonov in the final UFC PPV of the year ... but now the promotion will have to find a replacement fight.
Get well soon!