Wellington (0-2) are also sweating on the fitness of goalkeeper Carolina Vilao after Keane’s knee smacked into her opponent’s upper thigh just before her hamstring injury.
Vilao played on in visible discomfort before being replaced by Aimee Danieli for the second half.
Canberra easily opened up the hosts’ defence, with Maja Markovski pulling off a crafty assist to set up Heyman’s 100th goal for United.
The Phoenix, brought to life by Grace Jale and a brief canine cameo, came out firing after the main break to take 19 shots to eight, but could not salvage a point.