ASL (Approved Supplier List) is not a mandatory prerequisite for creating Contract Agreements. You can create blanket or contract purchase agreements without first defining an ASL, though ASL is useful for automated sourcing.
An Approved Supplier List (ASL) entry is a prerequisite for creating Blanket Purchase Agreements and Standard Purchase Orders when sourcing rules require it, but Contract Purchase Agreements do not require an ASL entry as a setup prerequisite — contracts simply capture legal terms tied to a supplier without going through the same sourcing validation. So the statement is false.