If a club terminates, say, a three year contract after one year, they normally don't just give him two years payoff and watch him sign for another club the next day. Instead, and depending on the contract he originally negotiated, there'll likely be a part-payout, with the rest due to be paid in instalments.
So that when/if he signs for another club within two years, for an equal or greater salary, then the former club's obligations usually cease. (Again, unless negotiated with his former club, a player cannot get a playing contract/salary a new club at the same time.)