Badosa beat Simona Halep in the first round of the tournament on Tuesday to set up the meeting with Sabalenka who remains in the competition despite the death of her partner, former NHL ice hockey player Konstantin Koltsov in what police called an apparent suicide.
The Spaniard, well known to be very close to the Belarusian, said she had spoken to Sabalenka at length since her partner's death.
"I don't want to talk about it. But of course. As I said before, she's one of my best friends. Yesterday I spoke with her a lot of time. This morning the same. So I know what she's going through," she told a press conference.
"I know the entire situation, what is happening. That for me is a little bit shocking also to go through that because at the end she's my best friend and I don't want her to suffer. It's a very tough situation," she added.
"At the same point playing against her, it's also uncomfortable. Yeah, but I don't really want to talk about it because I said I'm not going to talk about it. She's my best friend and I promised that," said Badosa.
World number two Sabalenka appeared at the tournament venue on Tuesday afternoon and practised on one of the outer courts.
She has not withdrawn from the tournament with organisers saying she intends to play.
"I know what she's going through. Honestly, for me hasn't been easy, too," said Badosa.
"I really don't know what to say, honestly. She's a strong woman. I think she will get the power from somewhere. I hope it's going to be a battle, a good match, and let's see," she said.
Badosa, once ranked second in the world, is now 80th in the rankings after suffering an injury-plagued 2023.
