After a record pot of $57.2million in 2019, the USTA has reduced the money on offer to players in this year's edition.
There will be no grudges held by Rafael Nadal against those players who take part in the US Open for prize money.
Madrid Open tournaments were unable to guarantee the tournament could be staged safely next month.
With the US Open due to start later this month, Alexander Zverev is unsure if he will play the tournament.
The last WTA and ATP events took place in March, and tennis has been a chaotic sport during the lockdown of the two main tours.
The US Open is schedule to start on August 31 in New York, however, Nick Kyrgios will not feature at Flushing Meadows.
With Ashleigh Barty skipping the US Open, Andy Murray expects other stars to do likewise.
It remains unclear whether the US Open will go ahead, but 2012 champion Andy Murray is preparing to take part.
After testing positive for coronavirus last month, Grigor Dimitrov discussed the effects of COVID-19.
The ATP and WTA Tour tournaments due to be played in China this year have been cancelled.