Police are investigating a crash at Mount Crawford earlier this afternoon.
Just after 12.30pm on Saturday, 1 December police and emergency services were called to Cricks Mill Road after reports that a motorcycle had left the road and collided with a tree.
The male rider was taken to the Royal Adelaide Hospital in a serious condition.
There were road closures in the area that have since reopened.
Anyone who may have witnessed the crash is asked to call Crime Stoppers on 1800 333 000, or online at www.crimestopperssa.com.au