It appears that McVay is perfectly happy running his system with players that fit the system. Hard to argue the results for the most part. So I doubt he has much interest in really utilizing Austin as a multi-purpose weapon and more like a gadget player who gets a few snaps here and there to keep defenses honest... mostly a decoy.
That said, McVay has said Austin could move into a WR role IIRC... But I think he would have to know the offense well and with his hamstring etc. perhaps he is just behind. The new TE from the Redskins is getting quite a few snaps. So my guess it McVay feels a lot more comfortable with guys that know his system and that outweighs a lot.
Anyway, I think we'll know a lot more about everything in 3 weeks or so. I don't know what to expect.