By Michael Donovan

The Sixers are hot as a pistol and the Celtics are in disarray.

So the Sixers’ 6-point spread when they play tonight may seem miniscule.

Especially since Celtics All-Star point guard Kyrie Irving did not travel with the team and has been ruled out for tonight’s game due to a right knee strain.

Irving came up hobbling after stepping awkwardly trying to fight through a screen in the first half of Boston’s loss to the Los Angeles Clippers on Saturday. Irving underwent an MRI Sunday which revealed no structural damage and he’s been deemed day-to-day by the team.

“Kyrie’s not going [to Philadelphia],” said coach Brad Stevens. “I have no idea what that means for Wednesday. Not playing [Tuesday].”

The Celtics host the Detroit Pistons on Wednesday night at TD Garden.

Irving was present for the team’s offday workout Monday but was dressed in sweatpants and watched from the sidelines. He ventured onto the court with an oversized blocking pad and playfully disrupted teammates as they got up 3-pointers after practice.

The Celtics are 7-2 without Irving this season but have struggled against the better teams in the league without him. Boston fumbled away a 28-point lead in Saturday’s loss to the Clippers while playing without Irving.