This is a specific injury that occurred during the Brisbane game.
They did not believe it was that serious, which is why he played (in some pain) against Cairns. I think it's a fair assumption to make, that playing probably made it worse.
The pain was not abating, which is why he was sent for scans.
What was at one point thought to require a simple draining of the haematoma, instead required more intensive surgery.
As was mentioned, the surgical incision has very large, and his thigh remains swollen and painful.
I'm sure we can imagine that even walking on that without pain is going to take weeks. Being able to train, you'd have to think would be months off, and presumably its going to take intensive therapy and rehab.