The 30-year-old immediately called for trainers and was helped off the ground in pain after kicking three goals in the intra-club hit-out.
West Coast confirmed Darling would be sent for scans on the injured ankle.
A serious injury for the player would be a significant blow for the Eagles, who are banking on Darling to lead their forward line this season in the absence of retired spearhead Josh Kennedy.
Darling kicked 34 goals in 2022, second only to Kennedy’s 37 for West Coast, and shapes as a prime attacking target alongside Oscar Allen.
Allen, who missed the entire 2022 campaign with a foot injury, showed promising signs during Friday’s match simulation as he kicked four goals.
West Coast had the competition’s second-worst attack last year, averaging just 65 points per game as they finished 17th in an injury-riddled campaign.
Champion Data statistics showed the Eagles had more players miss games through injury than any other club in 2022.
