Updated: 7:12 p.m.

The Sixers (18-7) will be in Boston Thursday night to take on the Celtics (17-6) at TD Garden.

This would've been Al Horford’s first appearance in Boston as a Sixer, but he's now listed as out. The veteran big, who opted out of his player option with the Celtics to join the Sixers this offseason, is dealing with left knee soreness and left hamstring tightness and just popped up on the injury report earlier today. Mike Scott will start in his place.

Boston is coming off a tough loss in Indiana last night. It was also a rough night for Boston in the injury department. Gordon Hayward, who just returned to the lineup after missing 13 games with a broken hand, was forced to leave the game after taking a shot to the nose. He's listed as probable. Marcus Smart (eye infection) and Robert Williams (hip) will both miss their third straight game.

Here are the essentials for tonight’s game:

When: 8 p.m. ET 
Where: TD Garden
Broadcast: TNT
Live stats: Follow here 

And here are three storylines to watch:

Big Al returns to Boston

Even though Horford won't play, the reception he receives should be interesting. When he signed his big free-agent deal with the Celtics back in 2016, it was a move that helped the revitalization of the franchise.

 

Though the fan reaction will surely be mixed with Horford returning with a rival, the Celtics’ players will be happy to see him again.

“He should be celebrated,” Jaylen Brown said to NBC Sports Boston. “Boston fans, they're gonna do what they want, right? Al came here, contributed, took this team the farthest it’s been since ‘08 [NBA champions]. Al served his time well here."

Brown added, “For me, he was a great leader, a great person … I know I’ll clap for him when they call his name. That’s just me.”

Just 23 games in a Sixers uniform and Horford has already had a similar impact on the players here.

“He’s just a real role model, in terms of how he lives his life,” Tobias Harris said to our Serena Winters. “There’s no real ups and downs with him. In my opinion, he’s the definition of a consistent person — comes in everyday, same attitude, same spirit, win or loss. The way he shapes his day-to-day life is inspiring for real.”

Embiid hears the criticism … and he agrees

In case you missed it, Charles Barkley and Shaquille O’Neal were blunt if their criticism of Joel Embiid after Tuesday night’s win over Denver. They said they felt like the All-Star center wasn’t putting in the effort to be great.

Embiid, who said postgame Tuesday that he wasn’t having as much fun this season, wasn’t offended by the criticism. In fact, he agreed with it.

“That’s what they do," Embiid told reporters. "Maybe they’re right. Maybe. I do think they are right. I do need to be more aggressive. Look to impose myself. Look to dominate. I think the whole season I haven’t done that and you can see the ways it’s affecting my efficiency and my stats. I guess I need to go back to having fun and just dominate. I get what they are saying. I think they are right and I gotta make a change.”

Embiid’s scoring numbers are down, but he’s still No. 1 in the NBA in terms of defensive rating for players averaging at least 25 minutes a game.

National TV, facing criticism, going on a tangent about not having fun, up against a rival — this seems like it’s lining up for a big night for the big man. 

J-Rich working off the rust

Josh Richardson was playing his best basketball as a Sixer when tightness in his right hamstring cost him six games. He returned Tuesday, but looked awfully rusty, going just 1 of 8 in under 20 minutes.

Though the Sixers went 5-1 in the games he missed, what the Sixers lost on both sides of the ball with Richardson out was evident. In the six games before his absence, Richardson was averaging 20.2 points while shooting a scalding 55.9 percent from three and 53.1 percent overall.

 

The skill the Sixers missed most was Richardson’s ability to create off the dribble, especially in the pick-and-roll. Brett Brown hasn’t run a ton of pick-and-roll in the past, but that’s mostly because of personnel. Richardson excels in that action and it’s one that helps the Sixers put other teams in a bind.

Richardson will still likely be on some form of minutes restriction.

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