In a backup center, the Sixers could do a lot worse than Al Horford. The 13-year veteran is an improvement across the board over the Sixers backup fives last season.

His pick-and-roll defense is one of the most valuable ways in which hes an upgrade. We got some insight from Horford on how he and the Sixers approach pick-and-roll defense, and we already have plenty of evidence how Horford helps in that area.

The Sixers have a variety of pick-and-roll coverages in their back pocket, but Horford explained their core principles in simple terms.

I think the biggest thing is just communicating, making sure that its the big man, the ones who are looking at everything and communicating to the guards, Horford told NBC Sports Philadelphia before the teams preseason finale. And then once we alert them, its important for the guards to be able to get up onto the ball and force the ball off the screen.

The aggressive objective of forcing the ball off the screen is often difficult to achieve. Matisse Thybulle does it well on the play below, with the help of early communication from Horford, stepping on top of Robert Williams screen and staying attached to Kemba Walker.

When the guard falls a half step behind in his effort to fight over the screen, the Sixers encourage rearview contests. Though Luke Kennard gets in front of Thybulle, the rookie effectively makes his presence felt from behind.

On both of the plays above, Horford drops into what assistant coach Ime Udoka calls center field, which still seems to be at the heart of the teams pick-and-roll coverage. When watching Horford defend the pick-and-roll, you notice his nuanced sense for how far to drop and when to do so.

The more familiar you get with different guys throughout the league, you know their tendencies, he said. Weve watched a lot of film and I have a good sense of how far I need to be up, how much I need to be back. Usuallycoaches do a good job of preparing us and letting us know. But its just a feel in the game. Its kind of to your discretion.

In the play below from the Sixers game against the Pistons, Ben Simmons is buried by Thon Makers screen. Horford drops a few steps into the paint initially in response to Simmonsfalling out of the play, but its not a panicked backpedal. He maintains his balance and doesnt give up more ground than he has to, tightly contesting Tony Snells runner.

This next example is similar to one that hurt the Sixers on many occasions last season, with the guard James Ennis, this case falling out of the play and allowing the ball handler an open mid-range jumper.

The subtle difference, however, is Horford has the skill in those spots to at least contest Brad Wanamakers shot, even if he cant truly put a hand in his face. Its the best Horford can do in this situation when the guard badly loses the first battle.

When Horford drops back into center field, his main goal is frequently just to buy his guard some time to recover. He gives Josh Richardson a chance to make an excellent rearview block on Gordon Hayward here, at first stepping up above the foul line to deter Hayward, then falling back to take Daniel Theis on the roll whenRichardson has worked his way back into the picture.

The result of a Sixers guard being soundly beaten by a ball screen is typically a 2-on-1 for theopponent, at least temporarily. Horford is strong at coping when such a moment occurs.

He positions himself in the right spot during the sequence below, staying in front of Tim Frazier while simultaneously blocking Andre Drummonds path for a roll to the rim. Drummond catching the ball nine or 10 feet from the hoop with Horford on top of him does not pose a serious threat to the Sixers.

Two-on-ones are, of course, not ideal for the defense. Frazier accelerates off Drummonds screen here, which seems to catch Richardson by surprise, and Drummond rolls hard to the rim. Fouling a career 54 percent free throw shooter is not the worst result for the Sixers, given the circumstances.

Udoka has notedhe thinks highly of Horford and Embiids ability to switch, but Horford was clear in saying thats not the heart of the Sixers approach.

I think that to our preference, we probably want to keep our matchups, even though we can switch at least thats what Coach has expressed to us., he said. Well do it how he wants us to do it, and if for some reason we need to make adjustments throughout the game, we will.

Horfords defense at the end of the first half of the Sixers regular-season opener shows why the team is confident in him switching. He comes up high on a pick-and-roll between Walker and Marcus Smart, thenthe Sixers make the late call to switch. Hoforfd does a decent job hanging with the three-time All-Star, and it sure helps to have Embiid behind him in the paint.

Having the foot speed not to get obliterated on a switch, knowing how to survive in the second or two when his guard is out of the play, using fouls in the appropriate moments none of these are flashy qualities. They're all skills Horford possesses, though, and reasonsthe Sixers can feel good about asking their guards to defend pick-and-rolls aggressively.

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