The Sixers don’t have an Al Horford problem. They have a Horford + Embiid problem. | David Murphy

The defining issue of the rest of the Sixers’ season has nothing to do with Ben Simmons’ jump shot. It has even less to do with focus, or hustle, or any of the other abstract qualities that have been serving as a crutch for people who are desperate to avoid the obvious. More than a third of the way through the schedule, it is clear where the dramatic tension of the rest of the season will reside. Brett Brown and his coaching staff need to figure out a way for Joel Embiid and Al Horford to coexist. Because right now, the pairing simply isn’t working.

The Sixers do not have a Horford problem. The veteran big man did not suddenly get old overnight. He has not lost his mojo. Ignore what his overall numbers say — over the last 10 games, he is averaging just 8.7 points and shooting .366 from the field — and look instead at his production when he is not forced to share the court with Embiid.

Table: Stats per 100 possessions. Source: NBA.com

Those are some radical splits, and while Horford has always been a consummate team player, the unfortunate reality is that the numbers do not look any better for the team as a whole. With Horford and Embiid on the court together, the Sixers are scoring fewer points than when either one of them is on the court without the other. When Horford is on the court by himself, they are outscoring opponents by an average of 5.5 points per 100 possessions. When Embiid is on the court by himself, they are outscoring opponents by 9.3 points per 100 possessions. But when both of them are on the court together, they are outscoring opponents by just 2.6 points per 100 possessions.

Table: Stats per 100 possessions. Source: NBA.com

This is the Rubik’s Cube that Brett Brown must solve, for both the Sixers’ sake and that of his continued employment. He might not have been the guy who decided that it was possible for the Sixers to be a functioning offensive team with two centers, but, given the nature of hierarchies, he will almost certainly be the first variable to be swapped out. The Sixers are not close to that level of desperation. Nor should they be, given the logistics of changing coaches in season. It has been little more than a week since they looked like the far superior team in a Christmas Day win over the team with the best record in the Eastern Conference. They have won five out of nine games against the teams who are currently ahead of them in the standings. Despite the preseason proclamations of the players, this roster was not constructed with the thought of winning 60 games in the regular season. They were built specifically with the goal of winning 12 out of 21 games against three teams. And we have seen nothing that suggests that the current mixture of personnel and coaching is incapable of that objective.

At the same time, the Sixers are in the midst of their longest losing streak since the 2017-18 season. They have lost at least three straight games on three separate occasions, after posting just one such streak all of last season. It’s nearly inconceivable that the Sixers will be able to trade Horford’s gargantuan contract. After all, we can reasonably assume that, five months ago, each of the 29 other teams in the league decided that it was not in their interest to sign him to that contract themselves. And even if there was a team that would have matched the offer, and would be willing to assume its obligations at the current juncture, it defies economic reasoning to think that they would part with anything that would leave the Sixers with a rotation that is equal or better.

Therein lies the puzzle. Even if there was a trade to be made, the Sixers are better with Horford than they are without him. Without him, they would be forced to play 15-20 minutes a night without Embiid and with some other center on the court. In those situations, admittedly rare, they have been outscored by nearly 13 points per 100 possessions this season. Against the Bucks, Horford played a big role in holding Giannis Antetokounmpo to one of his worst scoring outputs of the season. It is games like that where the Embiid-Horford pairing always made sense in theory. And, let’s keep in mind, the Sixers will always need to be ready for a scenario in which they must play without an injured Embiid for weeks at a time.

Given the offensive skill sets involved, the most likely solution will come primarily on the defensive end of the court. To date, the Sixers have not been all that more effective with Embiid and Horford together than with Embiid alone. They have been one of the top defenses in the league, but hardly the smothering bunch they fantasized about before the games started being played. A little improvement there would go a long way toward tipping the scales.

At the same time, the concerns on offense are not going away. As James Harden showed on Friday, sometimes, the only way to beat an elite scorer is to outscore him yourself. The Sixers need to get themselves to a point where they can do that with Horford at the four, especially given the way that they have played on the road.