Brooklyn Nets forward Ben Simmons has filed a grievance with the NBA in order to try to recoup the nearly $20 million in salary that the Sixers withheld from him this season, according to ESPN's Adrian Wojnarowski and Ramona Shelburne. This move was widely expected, and the grievance will now go through the league's arbitration process. 

Simmons requested a trade from Philadelphia this past offseason, and he made it clear that he didn't intend to play for the team again until his wish was granted. The Sixers began to withhold pay from Simmons when he didn't show up for the start of training camp. He ultimately returned to Philadelphia and rejoined the Sixers, and the team briefly stopped fining him once he said that he wasn't "mentally" ready to play. However, the fines resumed in short order when Simmons declined to meet with team doctors or share updates regarding his mental health progress. Obviously, Simmons and the team didn't see eye-to-eye on this issue. 

Simmons -- along with Seth Curry, Andre Drummond and two future picks -- was traded to Brooklyn in exchange for James Harden and Paul Millsap prior to the NBA's trade deadline last month. The trade didn't stop the fines though, as Wojnarowski and Shelburne pointed out. 

From ESPN: 

Beginning with Simmons' first paycheck on Nov. 15, Philadelphia began to claw back the per-game salary of $360,000 for each game Simmons missed this season. Because Simmons received a $16.5 million advance of his $33 million salary in the offseason, there wasn't enough money in each paycheck to cover the per-game deductions.

Minus the amount for escrow that was withheld by the NBA, the 76ers had been withholding nearly $1.3 million of Simmons' salary in each of his paychecks. That has continued since the trade to the Nets, who were made to deduct salary from Simmons' pay to wire to the 76ers, sources said. Because Simmons' last paycheck is on April 30, the deductions should carry over to the offseason. Once again. Simmons will receive a $8.25 million advance on July 1 and Oct. 1.  

Simmons has yet to play in a game for the Nets since the trade, as he continues to deal with a herniated disk in his back. He was initially expected to play in mid-March, but setbacks in his rehab derailed the original timeline. No new timetable for a return has been provided, but Simmons recently resumed light on-court workouts, and the Nets remain optimistic that his debut will come in the near future.