Short answer. Yes. The rule contemplates claims that are not yet due and claims that are contingent. Such a claim must be supported by an affidavit stating the particulars of it, in place of the affidavit required where the amount claimed is already due and owing.
What the law says
If the claim is not due, or is contingent, when filed, it must also be supported by affidavit stating the particulars thereof.
Rule 86, Section 9 — How to file a claim. Contents thereof; Notice to executor or administrator. Read the full provision →
Not-yet-due and contingent claims are both recognised
The rule addresses this in a single sentence, and it covers two different situations. A claim may be not due — the obligation exists and is certain, but the time for payment has not arrived. Or it may be contingent — whether anything will be owed at all depends on something that has not yet happened. Either way, the rule contemplates the claim being filed rather than held back.
Why waiting is the wrong instinct
Estate settlement works by gathering claims within the period the court fixes, so that what the deceased owed can be dealt with before what is left is distributed. A creditor who waits for maturity risks finding the estate closed and its assets distributed. The rule's willingness to receive immature and contingent claims is what makes it possible to participate without accelerating your own contract, and the practical reading is that you file and describe the position honestly.
The affidavit for this kind of claim
A claim that is due must be supported by an affidavit stating the amount justly due, that no payments have been made on it which are not credited, and that there are no offsets, to the knowledge of the affiant. A claim not yet due or contingent cannot truthfully be sworn to in those terms, so the rule substitutes an affidavit stating the particulars thereof — what the obligation is, what makes it immature or contingent, and on what the contingency depends.
Filing, and what goes with it
The claim is filed by delivering it with the necessary vouchers to the clerk of court and serving a copy on the executor or administrator. If it rests on a bond, bill, note or other instrument, the original need not be filed, but a copy with all indorsements must be attached. Where the affidavit is made by someone other than the claimant, the affiant must set forth the reason why it is not made by the claimant.
What filing early does not do
Filing does not accelerate the obligation. A claim that is not yet due remains not yet due, and a contingent claim remains dependent on the event that conditions it; what filing preserves is your ability to be heard in the settlement rather than to be paid at once. Nor does filing establish the claim — it must still be allowed, and the executor or administrator may contest it. The affidavit stating the particulars is therefore the document that does the persuading, and vagueness in it tends to be read against the claimant.