In a looming standoff that could have lasting implications for the NBA, Philadelphia 76ers All-Star forward Ben Simmons will not report for the opening of training camp next week and intends to never play another game for the franchise, sources told ESPN.

Simmons, 25, wants a trade out of Philadelphia and told management that he has no plans to wear an NBA uniform again until he's moved to a new team, sources said.

This is setting up a showdown for a Sixers franchise with championship hopes that will be greatly diminished without Simmons on the floor -- balancing the likely short-term losses with him sidelined against the long-term goals of getting a maximum trade return for Simmons.

Simmons explained his stance to ownership and management in a late August meeting and has had no direct contact with the organization for weeks, sources said.

Simmons has four years and $147 million left on his max contract -- including $33 million for 2021-22 -- and clearly understands the potential financial implications of sitting out. The Sixers could test Simmons' willingness to stay away by fining him considerable salary.

The Sixers have discussed Simmons trades throughout the league since the end of the playoffs, but they were disappointed in the offers and decided to hold onto him with hopes he would start the season and improve his trade value with his performance.

Sixers president of basketball operations Daryl Morey and coach Doc Rivers have told Simmons that they want him in training camp and on the floor to partner with All-NBA center Joel Embiid -- something that Simmons has told them he no longer wants to do, sources said.

Beyond the league's collective bargaining agreement, which provides the ability for the Sixers to withhold salary for a player's failure to provide services, the Sixers have their own set of rules that include fines for missing media day and each missed practice. The final resort for the Sixers could be to suspend Simmons for "failing to render services" once preseason games begin -- which could cost Simmons $227,613 for each missed game.

Simmons' contract is structured for him to receive 50% of his salary before Oct. 1.

Simmons' poor performance in a Eastern Conference semifinals loss to the Atlanta Hawks played a role in this drama playing out, but Simmons has become increasingly frustrated with his partnership with the Sixers over time, sources said.

ESPN front office insider Bobby Marks contributed to this report.