The Nets’ fifth and final starting spot is almost assuredly going to come down to a choice between Royce O’Neale and Joe Harris — an offseason addition or the longest-tenured Net.

And with the holdover nursing a sore foot that could keep him out of this preseason road swing, the newcomer could get an early head start toward claiming the job.

“Royce, he’ll be a great addition for us. Incredible IQ, feel for the game, both sides of the ball,” coach Steve Nash said last week. “He’s going to tie the room together on many occasions.”

Nic Claxton is set to get the nod at center next to the Big 3 of Kevin Durant, Kyrie Irving and Ben Simmons. The Nets have a plethora of wings they can deploy at off-guard or small forward, with O’Neale and Harris the leading candidates.

But Harris is still working his way back from two ankle surgeries and missed Thursday’s preseason loss with a sore foot. When asked Saturday if Harris would make the preseason-ending trip to Milwaukee and Minnesota, Nash gave a noncommittal “I think so.” And Harris didn’t participate in any events or move around much at Sunday’s Practice in the Park.

It could leave the door cracked for O’Neale — whom the Nets got from Utah for a first-round pick — to get an early leg up for the Oct. 19 season opener versus New Orleans.

While Harris is a deadeye shooter, O’Neale is a 3-and-D type for a Nets team in desperate need of defense.

With a 6-foot-9 swingspan O’Neale is one of the league’s better on-ball defenders. And while his spot-up shooting tailed off late last season, his ability to successfully guard top scorers will help.

“Royce is one of those players that you want on your team because he has a lot of experience,” Irving said. “He’s been through a lot of battles. He understands the nuances of the game and what it takes to win. They didn’t necessarily get over the hump in Utah, but he was a part of those teams that led the league in offensive efficiency. And then defensively, they were always an effort to go against.

“He brings his intangibles to our team really well. We can utilize him on that wing to be a defensive stopper — which we know he is — but also add some dimension on offense being a space-out shooter. He moves well, plays the game well, being in that Utah system for a long period of time. Moving the ball is something drilled in their head. He fits well.”

O’Neale, 29, had been the best perimeter defender on a Jazz team that enjoyed continuity. Now, he steps into a Nets team with not only new faces but also new systems at both ends of the court.

The result has been the Nets coming into Monday’s day off averaging 26.5 turnovers, by far the most in the league. (Memphis was next-worst at 23.7).

“It’s us being over-passive. You see guys trying to create for everybody else, get guys the ball,” O’Neale said. “[If we] limit our turnovers, we’ll be great. That’s the thing we had both games that we’ve got to minimize. Once the season starts, we’ll be really good.”

Through March 9 last season, O’Neale had shot 50.4 percent overall and a Jazz-leading 42.2 percent from deep. But in his last 22 games — six in the playoffs — his percentages fell to 32.9 and 28.7, respectively. He hit just 20 percent from behind the arc in the postseason.

It’s unclear if health played a role, but O’Neale did miss a game against the Thunder with a thumb injury. He’s shot 45.5 percent from the field and 40 percent from 3 this preseason, and he says the offense will improve with familiarity.

“For sure. It’s a new team. For myself coming in a new situation, I haven’t played with any of the guys on the team,” O’Neale said. “Ben was out for over a year, and Joe, everybody. So it’s us just coming together. We’re still learning about each other. So it does take time. We’re not going to just get it from Day 1.”