Austin left the field on a stretcher with a suspected broken leg early into the second half of the clash against Watford after a collision with a visiting player.
"We were all shocked by what happened and our thoughts were with Rudy," said boss Neil Warnock.
"Other things pale into insignificance when you see things like that.
"We'll know more about the full extend once the swelling has gone down and he has had a further scan."
Following the game, in which Warnock's men suffered a 6-1 thrashing and Jason Pearce was sent off, Warnock said: "I wanted to try and win the game with 10 men, but everything is irrelevant, it's the least of my worries when I think that we have lost Rudy for so long.
"When our lads knew about it, they were distraught."