Reigning champion Regan, who was widely tipped to take a fifth consecutive victory in the event, suffered what was described by her coach Sandy Richardson as a "freak accident" in training when she lost her grip on the high bar and fell to the ground.
Initial X-rays appear to have ruled out any fractures but the 19-year-old,who competes for City of Glasgow, is set to undergo further tests to determine the full extent of the damage. It is hoped the injury won't impact on her ambitions for the 2014 Commonwealth Games.
Giffnock-based Regan competed in Delhi in 2010, finishing fourth on floor. Her photograph features on the official Glasgow 2014 website with her target this summer to gain a medal on her two strongest pieces: floor and vault.
In an interview with Herald Sport last Friday - only hours before her accident - Regan confirmed she was in "a lucky position" having already gained the Commonwealth Games qualification standards for all-around, vault, beam and floor.
"The only one I don't have is bars," she said. "It's getting stronger. I have a few new moves to add in which should hopefully help up my score.
"I'm close to the qualification standard so it is a case of making a few tweaks. It's about whether you risk putting those new moves in now and potentially take a fall, which could affect qualification scores, or do it for the competition experience so you have that before the Games."