The 41-year-old Venus, who has seven Grand Slam titles to her name, said she would miss competing at her "favorite slam" and wished all the other players good luck
After careful consideration and following the advice of my doctors and medical team, I have decided to withdraw from the US Open to allow my body to heal completely from a torn hamstring
Former world number one Pliskova fell at first hurdle in the tune-up tournaments in Berlin and Eastbourne last month but the 29-year-old has yet to drop a set at Wimbledon.
Both the ATP and the women's WTA said it recommended players accept vaccine shots when available after some at the Miami Open this week expressed a reluctance to get vaccinated.
Professional tennis, which requires players to jet around the world, was shut down for five months last year as countries locked down borders to stem the spread of the virus.
Clijsters won the US Open in 2005, 2009 and 2010, lifting the trophy in Flushing Meadows in 2009 as a wild card after returning from her first retirement.
"She's (Barty) looking forward to playing against her. It's a great test because she is such a quality player, obviously improved out of sight from back then to where she is now."
The US Open finalist got a high percentage of first services in and never appeared to lose control against his fellow 23-year-old during the final match of the evening session on the Rod Laver Arena.
Zverev hit six more winners than Cressy, who is ranked 172nd.
Spieth has had his troubles off the tee in the Arizona desert, hitting just 43% of fairways, but he has hit 80% of greens in regulation and on Saturday he made the most of his chances.