The pair of former World No.1s will play the main draw at Flushing Meadows, which begins on August 28.
The Pole talked at length about the dificulties of finishing a match after midnight.
Vanity Fair magazine showcased established and rising American players before the US Open.
"I'm looking for perfection, which is not possible in this sport," Caroline Wozniacki said after Cincinnati setback.
"We have to find a solution for the late matches, there being unfair timing for people not playing at the same time," Sloane Stephens said.
Former No. 1 resting strained abdominal, hopes to play US Open.
For the first time ever, US Open champions will leave New York with an engraved, keepsake US Open trophy in hand.
