FWIW, the old NBL standard player contract contained clauses that required imports to be paid out for the season after a certain point in the season was reached. I suspect that's where the notion of a 'guaranteed contract' came from. The relevant clauses are quoted below.
This was a long time ago, when BA was still running the NBL. Since then, the NBL ownership first was transferred to the clubs and then to Kestleman. Also, this was the standard contract and players and clubs would have negotiated individual arrangements.
"10. DEFAULT AND TERMINATION
10.1 Events of Default by Player
(a) Each of the following obligations of the Player are essential terms of this
Contract (each an "Essential Term"):
(i) clause 2.2 (faithfully, diligently and to the best of the Player's skill
and ability perform duties);
(ii) clause 2.3 (act in the best interests of the Club and the NBL particularly as set out in their respective rules and regulations);
(iii) clause 4 (Player's duties);
(iv) clause 5 (fitness and injury);
(v) clause 6.2 (fitness);
(vi) clause 6.3 (injury and illness);
(vii) clause 6.4 (hospital and medical benefits);
(viii) clause 6.5 (disclosure of other contracts); and
(ix) clause 12.3 (disclosure of confidential information).
(b) If the Player breaches an Essential Term, the Club may give to the Player a written notice setting out the particulars of the breach and giving the Player a period of time (not exceeding thirty (30) days) in which to remedy the breach.
(c) If, after the expiration of the period specified in the notice given under clause 10.1(b), the breach has not been remedied to the reasonable satisfaction of the Club, the Club may:
(i) terminate this Contract; and/or
(ii) recover from the Player any loss suffered by the Club due to the
Player's default; and/or
(iii) exercise any of its other legal rights.
(d) The Player agrees that the Club is discharged from any liability to pay any further payments to the Player under this Contract from the date of termination.
(e) Nothing in this clause 10.1 affects the Club's other rights under the
provisions of clause 10 or this Contract.
(f) Notwithstanding the above, the Player agrees that if the Club or NBL is reasonably satisfied that the Player has committed a breach of the NBL Anti-Doping Policy then the Club is entitled to terminate this contract and in such case the Player agrees that the Club is discharged from any liability under this Contract from the date of termination.
10.2 Termination for Cause
(a) The Club may give notice to the Player that the Club intends to terminate this Contract under this clause as, in the Club's reasonable opinion, the Player is not playing or training for the Club conscientiously and to the best of his ability and skill or is otherwise in breach of this contract. A notice under this clause may specify the reasons that the Club has based its opinion on.
(b) The Club must within twenty-eight (28) days of the service of a notice under clause 10.2(a) allow the Player to have an opportunity to be heard by the Board of the Club in response to the notice.
(c) If, within twenty-eight (28) days of the service of the notice under clause 10.2(a):
(i) the Player has not approached the Club seeking to be heard under clause 10.2(b); or
(ii) in the reasonable opinion of the Club, the Player has not provided a satisfactory explanation, or remedy to the matters raised in the notice,
then the Club may terminate this Contract immediately.
(d) In the event that this Contract is terminated under clause 10.2(c), all obligations of the Club to make any payment to the Player under this Contract cease immediately and the Player agrees that the Club is released from all obligations to the Player including any obligations that arose prior to the termination.
10.3 De-activation
(a) The Club is entitled to remove the Player from the Club's active list of players at its sole discretion and may by written notice to the Player and subject to this clause; terminate this Contract by reason of the Player's de- activation by the Club.
(b) If the Club terminates this Contract under clause 10.3(a), then subject to clause 10.3(e), the Club must pay to the Player:
(i) if the Contract is a one year contract, then the remainder of the that years Salary;
(ii) if the contract is a two year contract and the player is terminated in the first year, then the balance of the first years Salary plus 50 % of the second years Salary. If the player is terminated in the second year of the contract then the remainder of the second years Salary is payable;
(iii) if the contract is a three year contract and the player is terminated in the first year, then the balance of the first years Salary plus 50
% of the second and 50 % of the third years Salary. If the player is terminated in the second year of the contract then the remainder of the second years Salary is payable plus 50% of the third years Salary. If the contract is terminated in the third year then the remainder of the third year Salary is payable.
10.4 Termination of Restricted Players
(a) A restricted player in the NBL competition may be employed on probation. The probation period shall end two months after the first regular season game.
(b) If such a player is terminated during the probationary period he will be paid one month's salary in lieu of notice, together with the reimbursement of any out-of-pocket expenses.
(c) Where a club seeks to terminate the employment of such a player after the conclusion of the probationary period, then it must be done in accordance with the provisions of clauses 10.1, 10.2 or 10.3 as applicable."
Clauses 10.1 and 10.2 A subsequent clause was specific to restricted players (imports) and read: