Manager Erick Mombaerts described it as a "big injury" in the immediate aftermath and their worst fears were proven right with Hendry going under the knife.
The former Dundee centre-back will now have an extended period on the sidelines.
In an Instagram post - showing a picture of Hendry in his hospital bed - the 24-year-old thanked Melbourne City and everyone who has sent messages of support.
He wrote: "It’s been a very difficult few days for myself was absolutely gutted to injure my knee on Saturday night.
"Happy to say I’ve had my op and hopefully all is well and now on the road to recovery, can’t speak more highly of @melbournecity staff an players and the support they have given me and hopefully can be back on the pitch asap, thanks to everyone that has messaged means a lot and I appreciate it!"