Rivers hurt his knee during Geelong’s seven-point win over Hawthorn, and Cats’ coach Chris Scott says he’s in some doubt.
"He hasn't tested it (his knee) to this point, so the jury's out a little bit there.
"… but I think we've been pretty clear with our policy on players that are less than 100 per cent, so if he takes the field on the weekend then he'll be absolutely ready to go.
"The indications post-game were that it didn't look like there was much damage there, but we still haven't established whether that's 100 per cent accurate yet.''
The Cats will also be without Steve Johnson (knee), despite the dangerous forward’s best intentions.
"He won't play this week. He'll be disappointed that I've said that,” Scott said.
Mitch Brown looks a likely replacement for Rivers, while James Kelly returns from suspension.
In casting his eye over the Kangaroos, Scott was quick to mention their assets.
"The way they can move the ball can be really dangerous. They've been accused of being a bit slow across the ground in previous years but I certainly don't see that in their footy these days.
"They have tall marking forwards that are going to benefit from quick ball movement as well. No-one's more acutely aware of their strengths than we are, having been jumped by them in this game last year."
