With Joel Embiid hampered by lower-back tightness and soreness, his availability for Thursday's home game against the Toronto Raptors was unknown Wednesday night.

Embiid missed a second straight game on Tuesday at the advice of the team's medical staff. The Sixers, set to update his availability Thursday morning after the game-day shootaround, have lost six of the seven games he has missed this season.

Embiid received continued treatment on his back Wednesday after having missed four of the last six games.

Before Tuesday's 101-95 loss to the Sacramento Kings, in which Embiid was a late scratch, Sixers coach Brett Brown was asked if Embiid would be missing any more time and he responded with uncertainty. Brown added that Embiid's situation was one that the team was taking day by day.

There have been some mixed messages. After Embiid played nearly 49 minutes in Friday's triple-overtime loss to Oklahoma City, Brown noted that the team elected to play Embiid the entirety of the three overtime periods because when the center sits he seems to have more discomfort. But, since that night, Embiid has been sitting.

The severity of the issue is not clear, and how much time Embiid will miss, or not miss, is not certain. What is clear and certain is that the Sixers are a completely different team without Embiid on the floor.

The Sixers will face the Raptors at home Thursday and again on Saturday in Toronto before their Christmas Day bout in New York against the Knicks — the Sixers' first Christmas Day game since 2001.

Monday's game is a highly anticipated one for which Embiid will no doubt want to be on the court. Brown has said Embiid is heavily involved in the discussions about when and if he plays, so it wouldn't be a surprise, because of Embiid's desire to battle the Knicks, if the Sixers elect to sit Embiid from now until then in order to preserve him for the marquee matchup.

"We've got to learn to play without him," Ben Simmons said Tuesday after losing another game while an injured Embiid watched from the bench.

There are a lot of things that change for the Sixers when Embiid does not play, and a lot of those variables directly affect Simmons.

Without a 7-foot-2 center as a threat, the defenses that already sag into the paint on Simmons have a lot less to worry about, so multiple bodies can keep Simmons from finishing at the rim. And, because Simmons is just a 54.8 percent free-throw shooter, creating contact is not a high priority for him.

The opponents know this, and they also know that Simmons is not going to shoot the ball. So, for the time being, because Simmons does not pose a threat from anything beyond a short floater, those sagging defenses are not going to change the way they are playing.

When Embiid's presence is absent, opposing defenses can not only clog the paint, but they can use their resources to cut off the Sixers' other options.

Relying on the shooting of JJ Redick and Robert Covington is a large portion of the Sixers' offense, and more often than not it's Simmons' job to find them in an open spot. Redick's and Covington's shooting has been streaky of late and the opposition can more readily cut off those passing lanes and close out sooner when Embiid's hulking body isn't ready to capitalize on the open lane.

In addition to the uncertain availability of Embiid and the lack of another shooter in Markelle Fultz, the Sixers also did not provide an update for Redick, who left Tuesday's game in the third quarter with tightness in his right hamstring. Redick also received treatment Wednesday.

What all of this boils down to is that Simmons, who knows the team needs to learn to play and win without Embiid, needs to be the one who leads the charge. Now is the perfect time to start shooting the ball. Opposing teams will not expect it, he'll have wide-open looks, and the team desperately needs a Simmons jumper to be an available option.

Against the Kings, Simmons started the game with two jumpers that he connected on, and it looked like the more aggressive side of Simmons was going to make an appearance, but he took just four more shots that night. That's not enough.

Brown has said he wants Simmons to be more aware and willing to shoot the ball, fans are clamoring for that part of his game to develop, and Simmons himself has said he needs to be more aggressive. It's time for it to happen.

This won't be the last time Embiid misses games, as other injuries are bound to pop up as the season wears on. Even if he misses, the threat of Simmons shooting the ball must become a part of the Sixers' game, and it needs to start now.