It's simple. You sign a contract with a player, thats on your books.
If a player has to medically retire, then you can go and recoup that money from an insurance policy if you have one, and that'll help your bottom dollar, but this code operates on a HARD cap. It must be maintained.
Exemptions should be looked at a case by case basis, and the bar should be basically set at the Alex McKInnon level. If you suffer an injury that has that kind of impact, we can all agree that the player should be paid out in full, supported for the rest of their life and the club not be stiched up with the cap bill... but for ongoing/accumulative, degenerative, debilitating injuries... na man, that's on you. You signed the deal knowing the physical toll this game takes on these players
Pay Sam his money, recoup it from an insurance policy if you have one and deal with the cap ramificaitons of your mismanagement/gamble.