By Matt Gregan, Sports Talk Philly Editor 
The 76ers will be facing off against their division rival, the Boston Celtics, in the first round of the NBA playoffs. In a rare occurrence, the 76ers managed to win the season series against Boston, 3-1. However, the regular season has been a long grind, and Philadelphia now finds itself without one of its top players, Ben Simmons, due to a knee injury he suffered in the seeding game against the Washington Wizards.
How will the loss of Simmons affect the 76ers' defense against Boston? How will the 76ers handle Boston's pesky group of defenders? Will Joel Embiid be able to dominate Boston's weaker group of bigs? The answer to those questions, and much more, below in our Philly vs. Boston series preview:
How will Simmons' absence affect the 76ers against Boston?
Ben Simmons, perhaps one of the NBA's best defenders, will be sorely missed in the 76ers' first round series against the Celtics. Boston brings a plethora of scorers, headlined by Jayson Tatum (23.4 points), Kemba Walker (20.4 points) and Jaylen Brown (20.3 points). Normally, the Sixers would pair Simmons – their best wing defender – on Tatum, but since Simmons is out that begs the question of how the 76ers defense will adjust and match up against Boston's offense?
The 76ers' starting lineup over the last couple of seeding games after Simmons got hurt was as follows: Shake Milton, Josh Richardson, Tobias Harris, Al Horford and Embiid. If they were to continue using that same lineup, this would be the presumed way that the 76ers would match up against Boston:
Kemba Walker – Josh Richardson
Jaylen Brown – Tobias Harris
Jayson Tatum – Al Horford
Gordon Hayward – Shake Milton
Daniel Theis – Joel Embiid
Richardson is the 76ers' best available wing defender, so it would make sense having him matched up against Walker, who is a crafty, quick scorer. Harris matches up well against Brown and Embiid will be matched up against Boston's big man, Daniel Theis. Milton will be forced to guard Hayward, the Celtics' least dangerous wing player. That leaves the matchup of Horford on Tatum, something the Celtics will look to exploit.
There are multiple ways the 76ers could look to defend Tatum, with none of them having a high chance of success. Horford, the former Celtic, could attempt to guard Tatum. Horford is not as quick as Tatum, but he has a size advantage he could use to play a "don't let him past you" style of defense. The 76ers can live with Tatum taking outside shots, but they can not live with Tatum getting easy drives to the basket, where he either will score or draw fouls and get to the free-throw line.
The 76ers could also attempt to match up Harris with Tatum. Harris would be a better matchup physically, but that would leave Horford to guard Jaylen Brown. Horford did a decent job defending Brown in the four times these two teams played each other, but it still is not a perfect solution.
Another potential solution to the 76ers' defensive woes could be to move rookie Matisse Thybulle to the starting lineup. Head coach Brett Brown mentioned on Sunday that he is considering moving Thybulle to the starting lineup. With the Embiid-Horford pairing not having worked well this season (the team has a minus-0.5 net rating when they are on the court together), it would make sense for Thybulle to replace Horford's spot in the starting lineup.
Thybulle is the NBA's best rookie defender and he has all the tools needed to stop Tatum. He has active hands and can make it difficult for Boston to get Tatum the ball. He is a quick, crafty defender who never gives up on a play and does a good job staying in front of his man. The one concern is that Thybulle has had struggles with getting into foul trouble, something the more experienced Tatum could take advantage of.
The most likely solution the 76ers will utilize against Tatum is to throw a bunch of looks at him. Philadelphia does not have the luxury to stick one player on Tatum and call it a night. The 76ers should use a combination of Harris, Horford, Thybulle and even Embiid at times to defend Tatum. None of those players are perfect solutions, but a combination of them all at different times could make it more difficult for Tatum to get into a groove throughout the series.
How will Joel Embiid fare against Boston's bigs?
Joel Embiid, on paper, should be able to dominate and have his way against Boston's weaker group of bigs. Boston has nobody who can stop Embiid in a one-on-one matchup, whether it be Daniel Theis, Robert Williams III or Enes Kanter.
However, Boston's head coach Brad Stevens has been able to figure out ways to make it difficult for Embiid offensively over the past couple of seasons. In three games against Boston this season, Embiid averaged 21.3 points, but he shot only 39.1% from the field. Stevens will throw double teams at Embiid every time he touches the ball in the post, therefore mostly negating the advantage Embiid has in any individual matchup.
There are ways around those double teams though, as evidenced by one mid-December game where Embiid dominated Boston to the tune of 38 points, 13 rebounds and six assists with only two turnovers. He consistently made the correct reads when double teamed, resulting in getting the ball out quickly to an open teammate for an easy basket. If Embiid can consistently make the right reads, it will be a long series for Boston.
Brett Brown vs. Brad Stevens: Part Two
Winning this series will take some adjustments being made by Brett Brown and the 76ers. When Philadelphia faced off against Boston in the playoffs in 2018, Stevens and the Celtics ran circles around Brown and went on to win the series in a decisive fashion. Will this year be different?
In 2018, it took until Game 4 for Brown to make any adjustments. Knowing that he could potentially be coaching for his job this season, Brown might pull the trigger quickly on a multitude of different potential adjustments.
One of those adjustments could be the way the team defends the pick-and-roll. Another adjustment could be moving Thybulle to the starting lineup, whether to replace Horford or Richardson. One thing we know relatively for sure is that Brown will have to make defensive adjustments on a game-by-game basis this series to figure out and utilize the best ways to match up with Boston's starting lineup.
In 2018, Stevens pulled all the right triggers and was ahead of Brown every step of the way. This year, while potentially coaching for his job, is Brown's opportunity to prove he learned from his past mistakes.
The X-factor: Philadelphia's bench performance
While many would say the x-factor this series would be who steps up to consistently defend Tatum, I'm going to branch out in a different direction.
The 76ers' depth could prove to be what makes or breaks this series. Playing without Simmons and with an inconsistent, shaky Milton in the starting lineup, the bench will have to produce in multiple ways for the 76ers to have a chance in this series.
Thybulle might be relied upon at times to guard Boston's top scorer, Jayson Tatum, something which very well could make or break the series. Alec Burks and Furkan Korkmaz, who both have turned it on in the NBA bubble, will need to continue to shoot consistently from 3-point range in order to stretch Boston's defense and help clear up the paint for Embiid to work. Raul Neto, averaging 17.7 points over the last three seeding games, is red hot and might be relied upon in short spurts to run the offense if Milton struggles. Mike Scott, another player who has picked up his performance over the last handful of games, can provide some toughness and scoring off the bench whenever needed.
This is the most depth Philadelphia has had in recent memory, now it is just time to make good use of it and make it count.
Prediction
The 76ers will have their hands full defensively against a talented Boston lineup, but if Joel Embiid can be the best player on the floor the 76ers have a chance in any series. There are some things lining up in the Sixers' favor, such as the boost off the bench that Alec Burks has provided lately or an ability to create mismatches on the offensive end.
With that being said, I think the 76ers win in a tight seven-game series worthy of the history between these two teams. Embiid dominates against a weaker, smaller group of Boston bigs and Brown makes the necessary adjustments defensively to keep Tatum from scoring 40-plus points per night.
