And anyway, substitute in Jason Cloke (or another currently uncontracted player) for Sam Fisher if you like. The crux of my point is the same - where does Collingwood find that extra $180K inside their Salary Cap?
I'd hope that there'd be a minimum contract level (say, whatever the minimum rookie contracts are). That would be the maximum that could be paid over the salary cap and could only apply if a player sustains a season ending injury. The injured player would not be allowed to play again for the rest of the season, to prevent teams abusing the system.
It's effectively allowed now.
Per your example, I don't have a problem with that because he's not gunna be lining up against Richmond in the AFL.