Brooklyn Nets rule Ben Simmons out for Game 4; All-Star forward reported back soreness, sources say

Within hours of his planned season debut, Brooklyn Nets guard Ben Simmons reported a return of back soreness on Sunday, sources told ESPN, and has been ruled out for Monday's Game 4 against the Boston Celtics.

After approximately 10 days of pain-free ramp up following recovery from a herniated disc, Simmons' admission at the team practice facility was met with surprise and disappointment. On the brink of a sweep to the Celtics, the Nets had hoped Simmons would be in uniform and active with the hope of coach Steve Nash using him in limited minutes, sources said.

While Nash and Nets players had publicly said that they were unsure whether Simmons would finally play in Game 4 on Monday, Simmons and the organization had discussed at length a plan for his debut to come on Monday in Game 4 at the Barclays Center, sources said.

Within the organization, Simmons had expressed eagerness and optimism through his ramp up about the possibility of making his season-debut in this series, sources said.

While Simmons hadn't been able to scrimmage with the Nets starters, there was still some hope his presence on the court could provide some help to a flailing team -- and allow Simmons to get back into an NBA game for the first time. A meltdown against the Atlanta Hawks in the 2021 Eastern Conference semifinals as a member of the Philadelphia 76ers set into motion a turbulent 10 months of trade requests, mental health issues and back trouble.

Simmons arrived with the Nets with Seth Curry, Andre Drummond and two future first-round picks in a blockbuster trade on February 10 that sent James Harden to the 76ers.

Simmons filed a grievance to challenge the nearly $20 million of salary withheld to him by the 76ers this season. Philadelphia has repeatedly insisted that Simmons was in breach of his contract under the collective bargaining agreement between the NBA and National Basketball Players Association and had the right to recoup the money advanced to him before the season.

The NBA and NBPA have been at odds on the issue, and now arbitration could set a precedent on how future matters of mental health and contracts might be handled. The 76ers have insisted that Simmons breached his player contract upon failing to show up for the start of training camp and refusing to play during the preseason and regular season.

Simmons arrived in Philadelphia near the end of the preseason but cited his mental health for the reason that his participation in team activities was so limited. The 76ers and Simmons disagreed over the degrees of access that the team and its doctors were allotted to Simmons to diagnose and affirm his mental health.

In an attempt to resolve the matter without arbitration, Simmons' representatives had several conversations with the Sixers since the blockbuster trade to Brooklyn for Harden, sources said.

Simmons, 25, is a three-time All-Star and will have three years and $114 million left on his contract beginning with next season.