World number two Aryna Sabalenka says her "heart is broken" after the death of her former boyfriend this week.

Konstantin Koltsov, a former ice hockey player, died at the age of 42 in Miami on Monday in what police have described as an "apparent suicide".

On Wednesday, Sabalenka issued a statement saying Koltsov's death was "an unthinkable tragedy".

The 25-year-old Belarusian, who is a two-time Grand Slam champion, is set to play in the Miami Open this week.

"Konstantin's death is an unthinkable tragedy, and while we were no longer together, my heart is broken," Sabalenka wrote in an Instagram post.

"Please respect my privacy and his family's privacy during this difficult time."

Sabalenka is set to play Spain's Paula Badosa - who described the pair as "best friends" - in the second round on Friday.

Badosa says it will be "uncomfortable" playing the Australian Open champion in the circumstances.

"It's a very tough situation," said the Spaniard, 26. "Yesterday I spoke with her. This morning the same.

"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."