"We tried to get Novak Djokovic to be allowed to get an exemption, but that wasn't able to happen," Blake told Tennis Channel.
"Obviously, we're one of the premier tournaments in the world, we'd like to have the best players that can play. We did all that we could. We tried to talk to the government, but that's out of our hands."
Florida Governor Ron DeSantis and the state's two U.S. senators were among those calling on the Biden administration to to allow world number one Djokovic to enter the U.S. and compete at the tournament he has won six times.
Djokovic is also missing the ongoing Masters tournament in Indian Wells, California due to his inability to secure the exemption.
The U.S. currently bars unvaccinated foreigners from entry into the country, a policy that is expected to be lifted when the government ends its COVID-19 emergency declarations on May 11th.
Djokovic, who missed last year's Australian Open after being deported from that country due to his vaccination status, has said he would skip Grand Slams rather than have a COVID shot.
He won his record-tying 22nd Grand Slam at the Australian Open in January. He has not played at Indian Wells or the Miami Open - which together comprise the "Sunshine Double" - since 2019.
A representative for Djokovic said the player would make no further comment regarding his absence from the Miami tournament, and he planned to return to the tour at the Monte Carlo Masters claycourt event that begins on April 9th.
Djokovic will then continue his preparations for the French Open in May by playing in the Srpska Open in Banja Luka, Bosnia.
