Ben Simmons has been ruled out of Game 4 of Brooklyn's playoff series against Boston, making it possible he won't play at all this season.

The Nets listed Simmons as out Sunday on the injury report for the game Monday night, when they will be trying to avoid a sweep by the Celtics.

Simmons has been working his way back from a herniated disk in his back and coach Steve Nash said before Game 3 on Saturday that the No. 1 pick in the 2016 draft had no setbacks after a 3-on-3 scrimmage earlier in the day.

But he also cautioned there was still a lot to consider as they weighed inserting Simmons into a game when he hadn't played since Game 7 of the Eastern Conference semifinals last year for Philadelphia.

Simmons then requested a trade and refused to play for the 76ers this season, citing mental health concerns. Philadelphia sent him to Brooklyn in February in a trade deadline deal for James Harden, but Simmons began to experience back pain soon after while trying to work his way back into shape.