"I and my team had to take one of the most difficult decisions - to skip this year's edition of the tournament in Sofia," Dimitrov said in a statement.
"Earlier today I had my last medical consultation. Unfortunately I will not be at 100 percent ready for next week. If I play it would lead to additional risks and complications."
Local favourite Dimitrov will be replaced by Swiss Stan Wawrinka, who is trying to resurrect his career after suffering a knee injury.
Serbia insist Djokovic will play at Olympic Games
"On back of disappointing news of Dimitrov injury, great that triple grand slam champion Stan Wawrinka will play Sofia Open," the tournament director Paul McNamee said on Twitter.
South Korea's Chung Hyeon will also miss the tournament after failing to recover from the foot injury that forced him to retire from his Australian Open semi-final against Roger Federer.
Murray: I don't want it to be my last Wimbledon
Murray: Djokovic has unique claim to be GOAT