Former men's world number one Novak Djokovic said he will not play in the US Open which begins on Monday as COVID protocols mean he cannot travel to the United States.

It is the second Grand Slam the 35-year-old Serb will miss due to not being vaccinated as he was deported prior to the Australian Open earlier this year.

"Sadly, I will not be able to travel to NY this time for US Open," tweeted Djokovic, a three-time US Open champion.