After Djokovic's vaccination saga in Australia, the 34-year-old said he was willing to miss big tournaments "because the principles of decision-making on my body are more important than any title or anything else".
The Serbian star admitted that he has received no vaccination so far, which limits his ability to travel internationally, with his latest problems coming when trying to enter the US.
The CDC (Centers for Disease Control and Prevention) confirmed earlier this week that all athletes need to be vaccinated to enter the country.
As a result of such regulations, Djokovic had no choice but to miss out on more tournaments this month, with the world No.2 pulling out of both the Miami Open and the Indian Wells.
Djokovic took to social media to inform fans on his withdrawal:
"While I was automatically listed in the @bnpparibasopen and @miamiopen draw, I knew, given the entry requirements to the US, it would be unlikely I'd be able to travel there.
"But as international Covid regulations are always being amended, I wanted to wait and see if anything would change.
"The CDC confirmed today that regulations are not changing which means I will not be playing in the US.
"I know my fans are looking forward to seeing me play again and I hope to be back playing for them on the tour soon. Good luck to everyone who is playing in the US in these great tournaments."
Djokovic will be eager to win back his world No.1 title after losing it to Daniil Medvedev earlier this month, but as the only tennis player within the top 100 to not be vaccinated, he's endured a rocky start to the season.
With France's Covid-19 regulations changing recently, Djokovic will hope to feature in the French Open at the start of May.
As for the Miami Open and Indian Wells, Djokovic's withdrawal means that Grigor Dimitrov will move into Djokovic's space in the draw.
The Indian Wells Twitter page confirmed the news: "Novak Djokovic has withdrawn from the BNP Paribas Open. As the next player in line to be seeded, Grigor Dimitrov will move into Djokovic's space in the draw, and a Lucky Loser from qualifying will move into Dimitrov's space in the draw once qualifying is complete."