When asked about the still-pending Kawhi Leonard trade between the Clippers and Raptors, NBA commissioner Adam Silver said the onus for the delay lies strictly with the teams involved and not with the league.

The NBA’s investigation into a potentially fraudulent Kawhi Leonard sponsorship deal has expanded to look into multiple suspicious issues.

At the center of the delay is a league probe into whether the Clippers circumvented the salary cap by routing money to Leonard through a $28 million endorsement deal with the now-bankrupt firm Aspirat...