Is he the defensive player of the year, or the scorer that remains stuck on a plateau?

Is he a superstar or an All-Star, a centerpiece or a nice piece?

If Allen Iverson was The Answer, then Ben Simmons is The Question. This Sunday marks the start of his chance to respond.

The 2021 NBA postseason might not be Simmons’ last chance to prove that he belongs, but it could be his best one. Everybody wants to know whether a player like him can win a title while playing alongside a player like Joel Embiid. Well, the NBA may never be more winnable than it is right now, which makes these next couple of months a critical test of the legitimacy of the blueprint they unveiled five years ago. We know who Embiid is. We know who he can be. The onus is on Simmons to be the partner he needs.

Maybe that framing sounds excessively dire, and maybe it is, but the NBA is a dire league. One year, you’re feeling fortunate to have drawn the Heat or the Nets in the playoffs. The next, you are trying desperately to avoid them. The Sixers have a coach who understands this. They have a president who knows that the precipice of a championship can be the most difficult spot to be. As often as Doc Rivers and Daryl Morey have praised Simmons this season, there is no talking around the fact that, just five months ago, they were seriously considering trading him. By the end of this postseason, the implications of January’s James Harden intrigue could become even harder to ignore.

» READ MORE: The Sixers’ Tobias Harris: ‘This is the opportunity we have to do something great’ | Off the Dribble

For the Sixers to win a title this season, they need Simmons to be the player he can be rather than the one he has more often than not been. There’s nothing unfair about saying that if a championship is your benchmark. The circumstances are a different story. They’ve never been entirely fair to Simmons. Had he been drafted by a different team, with a different foundation, and different management during its formative years, he could easily be playing on a team that the Sixers would dread facing in these playoffs. The roster that you’d build around him looks a lot different than the one that you’d build around Embiid. But Embiid was here first, and Embiid is the better player, and that has always left Simmons needing to be something different from his optimal self.

Even so, he has been a very good basketball player, much better than a lot of folks give him credit. He plays for a very good basketball team, and that team will continue to be very good for as long as he wears its uniform. A lot of that has to do with the guy who plays center, but Simmons’ presence is a significant piece. We saw that in the playoffs last year, when the Sixers were swept with him on the sidelines. Simmons and Embiid are not a perfect tandem, but for however long they remain together, their team will be a threat to do what it did this year: win 68% of their regular-season games, capture the No. 1 seed, give the paying customers their money’s worth.

Question is, is all of that enough?

We know where Sam Hinkie stood on the matter, and Morey has made it clear where his sympathies lie. Championship or bust, he said earlier this season. He did not leave Houston in search of another place where he could lose in the conference finals. This is Simmons’ moment to show he feels the same way.

“We’ve put ourselves in a good position,” Simmons said after the Sixers clinched the No. 1 seed, “but we ultimately want to win a championship.”

More than anybody, it’s on him to make those words a reality. We’ve seen it this season. Not often, but we’ve seen it. The player the Sixers need is the player they saw back on Feb. 15, when Simmons scored 42 points on 15-of-26 shooting against a Jazz team that is currently the Western Conference’s top seed. The performance came in the midst of an 18-game stretch in which he averaged 19.3 points while attempting 13.2 shots per game. He shot .595 from the field, averaged 5.4 foul shots per game. He was as active, and aggressive, and engaged as we’ve seen him. If that’s the player the Sixers get this postseason, you can forget all of this hand-wringing. There will be a new banner hanging in the Wells Fargo Center rafters next season.

The flip side is also true. In the Sixers’ last 22 games, Simmons averaged 11.4 points and 8.2 field-goal attempts per game, the lowlight coming in a blowout loss to the Heat on May 13. He scored eight points that night. He attempted just six shots. If that’s the player the Sixers get this postseason, they won’t have a choice but to consider the more drastic of their options.

“I tell him all the time, I want him to be aggressive every single game,” Embiid said last month of his running mate. “Whether he is making plays or whether he should look for his shot, he has to be aggressive and make guys on the other team guard him.”

» READ MORE: Fatherhood inspires Joel Embiid as NBA playoffs get set to begin

There are no more excuses. The Sixers are the No. 1 seed. Their road to the Eastern Conference Finals is as clear as it could possibly be. They are healthy. They are experienced. They are well-coached. The Nets may never be as vulnerable as they are this year. The Bucks and the Heat have plenty of ways they can improve. The Celtics will be looking to land themselves another star.

For Simmons and the Sixers, the question is one and the same.

If not now, then when?