The NBA has begun an investigation into a potential tampering violation by the Philadelphia 76ers and their signings of James Harden, P.J. Tucker and Danuel House Jr, according to ESPN’s Adrian Wojnarowski.

The league is interested in the circumstances surrounding Harden declining his $47million player option to sign a two-year, $68m contract that includes a player option for the second year of the deal.

Questions have been raised about whether there was a handshake agreement in place on a future contract – which would be in violation of collective bargaining rules.

Harden’s decision to decline his option gave Philadelphia more flexibility to sign Tucker and House.

"Taking less money this year to sign as many players as we needed to help us contend and be the last team standing was very, very important to me," Harden said in an interview this month. "I wanted to show the organisation, the Sixers fans and everybody else who supports what we're trying to accomplish, what I'm trying to accomplish individually, that this is what I'm about."

Tucker signed a three-year, $30m contract, and House signed for $8.4m over two years. The 76ers were able to sign Tucker to the full mid-level exception and sign House to the bi-annual exception only because Harden declined his option.

According to the report, 76ers president of basketball operations Daryl Morey has already begun answering questions from league attorneys.

With tampering often a potential issue, the NBA approved stiffer penalties in 2019 and stripped a draft pick from the Chicago Bulls for early contact with Lonzo Ball in 2019, and the Miami Heat for doing the same with Kyle Lowry last summer.