The Philadelphia Flyers' attempt to trade defenseman Tony DeAngelo back to the Carolina Hurricanes is being held up by a clause in the NHL collective bargaining agreement, an NHL source confirmed Monday.

The Flyers acquired the restricted free agent rights to DeAngelo, 27, from the Hurricanes on July 7, 2022, for three draft picks. Former Philadelphia general manager Chuck Fletcher signed him to a two-year, $10 million contract.

GM Danny Briere, who replaced Fletcher and has been aggressively reshaping the roster this offseason, had a deal in place to send DeAngelo back to the Hurricanes for a prospect, with Philadelphia retaining 50% of his salary.

Rule 50.5 of the NHL CBA protects against a team trading a player, having another team pick up a percentage of their salary, and then quickly reacquiring that player at a reduced cap cost. It states that "under no circumstances may a Club reacquire, as part of a Retained Salary Transaction, the contract of a player who was on that Club's Reserve List within the past calendar year."

If the Flyers didn't retain any salary, the transaction would be allowed. But since the salary retention is a key to the deal, it's being held by the NHL. The league is expected to continue to discuss the matter at the NHL draft this week in Nashville, Tennessee.

DeAngelo had 11 goals and 31 assists in 70 games with the Flyers. He was scratched on multiple occasions by coach John Tortorella late in the season. DeAngelo played one season with the Hurricanes in 2021-22 and tallied 51 points in 64 games.

The Athletic first reported the NHL investigation.