Once you get past the initial weirdness of the Sixers acquiring Al Horford, the logic of the move is pretty straightforward. The Sixers are putting the health of franchise center Joel Embiid at the top of the priority list and ensuring they can hold down the fort with or without him on the floor next season.

But there is a subplot to the Horford signing that has gone under-discussed in the month following the opening of free agency. Is it possible that signing Horford undercut the value of Tobias Harris, who the Sixers have committed to investing $180 million in this summer?

We won't really know what this all looks like until the Sixers take the floor for training camp/preseason in late September. Even this far out, though, the consequences for Harris (and thus, the team) are potentially significant.

Harris is changing his primary position from his best years

Entering the league in 2011, Harris' skill and tool package left him trapped between positions to a certain degree. Thankfully for the Tennessee product, he entered the league at a time when the dreaded label of "tweener" became less consequential than it has ever been. The rise of small ball has flooded lineups with switchable wings, typically bookended by a guard and a rim protector to tie it all together.

But even in that context, teams struggled to figure out where Harris fit best on the floor during his early seasons in Milwaukee and Orlando. It was not until he arrived in Detroit, which coincided with the arrival of a consistent three-point stroke for Harris, that teams figured out his best position was at power forward. There, his lack of elite burst is not as much of a problem in individual matchups, and his scoring versatility helps him stand out more as a four than he would as a true wing, competing against a handful of the league's best players.

(A note here: there are resources, e.g. Basketball-Reference, suggesting Harris played as low as two percent of his minutes at small forward last season. But those numbers undersell lineup combinations/counts available at other resources surveyed for this story. Because of the conflict in information, those numbers and estimates of how often the numbers say he played SF throughout his career are largely being omitted here, though a steady decline in minutes as a SF over his career is certainly verifiable.)

It is hard to separate Harris' on-court numbers in any of those early seasons from the team situations around him. The Magic, for example, were and are notorious for their ultra-big roster construction, forcing players down in the lineup who would be better served moving up. Whether Harris was a three or a four, it was going to be tough from a pure talent perspective to put five-man groups on the floor who could consistently win minutes.



But in Philadelphia, Harris walked into a situation where he was a perfect fit as a four. And indeed, the Sixers had a lot of success with Harris playing the four in the regular season and the playoffs. Last year's starting group had a point differential of +22.4 per 100 possessions in the regular season, and in the playoffs, they were even better, with the starters posting a +26.7 NETRTG across 353 postseason possessions.

No playoff lineup registered more than 54 possessions with Harris at the three, and the samples are probably too small to make any sweeping conclusions. But there's one group I want to hone in on in particular, as we may end up seeing a slight variation of it next season.

Where there is cause for concern

There was a group that played together in the playoffs (Simmons-Redick-Harris-Scott-Embiid) that may end up getting some time this year, albeit with Josh Richardson in place of JJ Redick. In both the regular season and playoffs, though, this grouping was a disaster for Philadelphia.

Portion of season NETRTG Regular (89 possessions) —5.7 Playoffs (46 possessions) —29.8



No one credible would try to determine Harris' value at small forward from less than a game-and-a-half of data, so I won't do that here. The most-played playoff lineup with Harris at small forward also crushed to the tune of a +33.2 NETRTG, though that the group featured Jimmy Butler at the point and only played 54 possessions together, so it's tough to project anything based off of that for this year's team.

There are two primary reasons I think Harris' assignment shifting is worth keeping an eye on:

Going strictly on the eye test, if you asked most people what Harris' biggest weakness is as a defender, they would point to the difficulty he has defending players in space. Even though modern four men are getting sleeker, Harris generally got to defend more stationary players once he started playing there on a more full-time basis. Lineups performing well with Harris as a true small forward are no longer a luxury, they are necessary for the Sixers to contend. The team is built around the five-man grouping of Simmons-Richardson-Harris-Horford-Embiid.



Harris' lack of elite burst hurts him when he has to defend smaller, quicker players, as it leaves him mostly unable to recover from mistakes or misreads. It's not that he isn't committed to or interested in defending, but his instincts can work against him. When he tries to play aggressive and blow up handoffs, for example, he often overpursues the play and creates a lane for drivers to exploit. Harris gets a lot of the downside of aggressive defense without also gaining the ability to produce turnovers.



Away from the play, Harris has made some strides in his reads and has improved as a help defender, which is often more important than one-on-one defense in the modern NBA. Caring is half of the battle. Still, the further down he guards in a given lineup, the more likely it is he'll have to track movement and navigate through screens, which minimizes the benefit of his strength advantage against more wiry players.

When the Sixers needed to change things up after a brutal Game 1 loss to the Raptors, Brett Brown's first instinct was to slide Harris up defensively, asking Joel Embiid to guard Pascal Siakam after his fellow Cameroonian torched Philly in Game 1. After Siakam and Kawhi Leonard shot a combined 10/13 with Harris guarding them in the opener, Brown matched him up with Marc Gasol, where he could mostly hide for long stretches of games.

That is not really an option for Philadelphia this season. Asking Horford to play as much power forward as he will this season is already going to test the Sixers' lineup construction. If Harris doesn't prove up to the task of checking wing players, the Sixers will have the unenviable task of deciding whether they should sit one of their big-money players in crunch-time and whether they need to sub offense-defense in order to tie everything together.

One more thing to keep in mind — the Sixers are asking Harris to guard more true wings as they're also asking him to take more control of the offense. The Sixers are (and should feel) confident about Harris' ability to take on more responsibility as a scorer. Whether he can do that while taking on more challenging defensive assignments is another matter entirely, and should never be taken for granted.

How Philadelphia might get around it

The good news for Harris is that unlike last season, there are no weak links in the defensive chain around him. Even if he struggles with the shift to guarding smaller players, in theory, the Sixers can stick him on the team's weakest perimeter player every time the starting lineup is on the floor.

Richardson replacing Redick in the starting lineup is huge in this way. The former Heat wing is a natural candidate to guard the opponent's best guard every night, leaving Ben Simmons to take on the best wing on the opponent (or perhaps Al Horford in specific matchups, e.g. Giannis Antetokounmpo). The Sixers no longer need to find a place to hide Redick in crunch time — or in general — and handing Harris the Redick-level assignments will give them a bigger and more athletic defender than they had before.

One of the problems last year was also a matter of commitment. Philadelphia's regular-season defense suffered at times last season because multiple players at a time were mailing it in on defense. Richardson and Horford both pride themselves on being complete, two-way players who help establish a defensive identity. The Sixers' bench is also deeper now than it was to start last season and even their young players are defense first.

For the regular season Sixers, this is unlikely to be too much of a problem. The league doesn't ramp up the matchup hunting until the postseason begins and in-depth scouting really comes into play, and with Embiid expected to take more rest days this year, Harris will have plenty of opportunities to play full games at his more natural four spot. Even when everyone is healthy and active, Harris should get basically all of his minutes with bench-heavy lineups in the frontcourt.

But among Philadelphia's many questions to answer this season, Harris' ability to guard smaller players may end up being one of the biggest.

Whether we are talking about their ability to space the floor or if they can create credible defensive matchups with their five-man core, ultimately the mystery is the same. Does this group fit together when the stakes are the highest, and what will they do if it doesn't?

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