Struve, who fights out of south Florida, revealed the injury on his Instagram account Thursday.
"Bad news folks," Struve wrote. "Unfortunately I won't be able to fight in Halifax, February 19. I'll be undergoing surgery to fix a torn labrum in my left shoulder tomorrow afternoon."
Struve, 28, said his estimated recovery time is four months.
The bout was supposed to headline UFC Fight Night at Scotiabank Centre in Halifax, Nova Scotia. The UFC has not announced whether dos Santos (18-4) will remain on the card.