Her deal finishes on 30 June and will not be extended.
Brooks joined Blues in January 2019 from Sheffield United.
The former Manchester City graduate came in to compete for the number one jersey after Ann-Katrin Berger's departure.
In the main she has been back-up to Hannah Hampton, who went on to establish herself between the sticks at Blues.
Brooks made three appearances this season: two in the Continental Cup and in the FA Cup at Sunderland.
Everyone at Blues would like to thank Alex for her service and we wish her all the best in the future.