The status of Ben Simmons remained uncertain, and head coach Brett Brown said he had no idea how long the 76ers point guard would be sidelined with a back injury.

The Sixers had said Sunday that Simmons would miss Monday’s game against Atlanta with a lower-back injury that he aggravated Saturday in a 119-98 loss at Milwaukee.

A team spokesperson said that Simmons wasn’t with the team as he receives further treatment and evaluation. The Sixers issued a statement that they were working in conjunction with Simmons and his management team on a comprehensive evaluation.

The evaluation process is expected to be completed within 24 hours. According to the Sixers, more will be known then. But it appears this isn’t a short-term problem. ESPN reported that Simmons will be sidelined for an undetermined period.

Simmons missed the 112-104 overtime win over Brooklyn last Thursday with lower-back tightness He returned Saturday against Milwaukee but played just 4 minutes, 44 seconds before leaving the game for good after he aggravated the injury.

Brown tried to remain positive while his two-time All-Star is sidelined.

“With 25 games left, we’ve taken a hit with Ben and I do see it this way,” Brown said before the game. “I’m not spinning it, it’s an opportunity for us to learn, and something will emerge and we need something to emerge ...."

Brown said that how the Sixers played in Simmons’ absence will tell a lot about the team.

Brown said there are several options for replacing Simmons. One move that should occur is having Josh Richardson, the staring two-guard, play more at the point.

“I think we have a few guys that can handle the ball well, so that’s by committee, but we’ll be able to hold it down for him,” Richardson said before the game.

Shake Milton joined Richardson in the starting backcourt against the Hawks. The other starters were Joel Embiid, Tobias Harris, and Al Horford, who returned to the starting lineup after coming off the bench the previous three games.

Harris makes quick comeback

Harris, who suffered a right knee bruise in Milwaukee and was originally listed as doubtful, was in the starting lineup against the Hawks. This season Harris has played in every game. He appeared in at least 80 games in each of the previous three seasons.

He suffered the injury in the second quarter but continued to play.

“I probably should have stopped [playing] right there when it happened, but I kept going on," Harris said before the game.

Harris added that he wouldn’t take the court if he didn’t feel he could help the team.

“I feel OK enough to give it a go and play and I feel like I can be productive,” Harris said. “I was in a lot of discomfort, but [Monday] I felt a little better.”

Pelle out

Center Norvel Pelle wasn’t available against Atlanta with an upper respiratory illness.