The NHL will hire an outside firm to determine whether the Flyers talked about a timeline for Pronger's potential retirement before the seven-year, $34.45 million contract was signed.
The NHL apparently is concerned that the front-loaded contract for an older player like Pronger violates the spirit of the salary cap, according to Philly.com. Since teams know that players might retire instead of playing for a lower salary in later years, an extended deal allegedly lowers the average salary cap hit.
If Pronger -- who will turn 35 before the seven-year extension kicks in next summer -- retires, the Flyers would take an average cap hit of $5 million annually for the life of the contract, according to ESPN.
With his new contract, Pronger will be making $7.6, $7.6, $7.2 and $7 million in the first four years, $4 million in the fifth year and then $525,000 in each of the last two years -- or, a tad under $5 million annually.
Meanwhile, Pronger isn't the only player whose contract is under investigation. Marian Hossa's 12-year, $62.8 million contract with the Chicago Blackhawks is also being looked into.
The Blackhawks released a statement on Friday denying any violation of the CBA, ESPN reports.