Australian Open champion Aryna Sabalenka said Saturday she is "not 100%" certain of playing her first round Wimbledon match due to a "really rare" shoulder injury.

Sabalenka, a two-time semi-finalist at the All England Club, had to quit her quarter-final match against Anna Kalinskaya in Berlin last week due to the problem.

"I'm not 100% fit now," admitted the 26-year-old Belarusian who is due to face 106th-ranked Emina Bektas of the United States in the first round on Monday.

"We're doing everything we can with my team to make sure I'll be able to play my first match here. But, no, I'm not 100% ready."

When asked if there was a chance she may withdraw on Monday, she said: "There is always a chance, yeah."

Sabalenka said her doctors had told her that she was "just the second or the third tennis player who injured the (shoulder) muscle".

"It's really a specific injury, and it's really a rare one."

Meanwhile, Sabalenka defended her decision to skip the Paris Olympics which she made the week after her defeat to Russian teenager Mirra Andreeva in the last-eight of the French Open.

She said she made the choice to prioritise her health, wary of switching back to the clay courts of Roland Garros, where the Olympics tennis event is played.

"I decided to sacrifice the Olympics for my career, for my health," said Sabalenka.

"I really hope that I'll be able to play the next Olympics."