Opal Bec Allen remains in coach Sandy Brondello's basketball World Cup calculations, despite her rib injury forcing her out of Thursday's quarter-final prematurely.

One of Australia's senior players, Allen sustained the injury in a contest for the ball against Serbia on Sunday.

She was assisted from the court struggling to breathe and eventually left Sydney's Qudos Bank Arena in a wheelchair as walking was causing her pain.

Having been cleared of structural damage, Allen made it onto the court in the Opals' first match of the knockout stage but was in noticeable discomfort and subbed out after only two-and-a-half minutes of game time.

"I'm struggling, I think everyone knows," an emotional Allen told reporters after Australia's 86-69 win over Belgium.

"I really needed to try for myself. Not today, but hopefully tomorrow (in the semi-final)."

The Opals are determined to keep giving Allen opportunities to prove her fitness, but coach Sandy Brondello said she would not be pressured to play.

"She's a game time decision," Brondello told reporters.

"Bec is an important part of this team but if she can't go, I'm not going to try and force her.

"We've got quality players that can replace her."

Sara Blicavs replaced Allen in the starting line-up against Belgium and has been rooming with her on tour.

The pair have been good mates since they were teenagers and Blicavs said she would be doing everything in her power to help Allen's recovery.

"I'm looking after her, I'm her nurse, I'm her work wife as we call each other," Blicavs told AAP.

"I know that she desperately wants to be back out there and gosh we miss her.

"I just keep reiterating to her that there are more important things in life than basketball."

Blicavs said she had faith her teammate would line up either in Friday night's semi-final against China or in the match afterwards, where Australia will compete for either the gold or bronze medal.

"I've got high hopes for (Allen playing in) the semi, if not I think she's going to play through the pain, especially if it's a gold medal match," Blicavs said.