PHILADELPHIA — With their three big men all down, the Nets handed young Noah Clowney a start at center Wednesday.

The second-year battled — but not enough, roughed up by Andre Drummond in a 117-95 preseason loss.

“I think he did not fight hard enough. Obviously it is a great learning experience for everybody,” coach Jordi Fernandez said. “There’s technicalities obviously, like how you front somebody, how you push him out. It’s definitely a challenge. But I would have liked to see a better fight.

“And it’s just not just Noah, it’s everybody else. I can go down the line with Keon [Johnson], Ziaire [Williams], everybody, the starters. At some point, this is not about you. This is about us. And if we don’t play hard as a team, we’re just not good enough.”

With Nic Claxton and Day’Ron Sharpe — the only two pure big men on the roster — both out, Ben Simmons had started the first two games.

But Sharpe got a scheduled night off as the Nets manage his return from surgery.

Clowney had 11 points, eight rebounds and two blocks.

But Philadelphia moved the spindly sophomore off the block and got into the paint. It was a tough lesson.

“Yeah. You gotta grow from every game. You can take the game one of two ways,” said the 20-year-old Clowney. “I gotta grow from it. If I don’t grow from it then I don’t believe. … At this level, you’re either gonna get better and learn from it or you’re gonna go the other way.

“The size of the person I’m going against is not what concerns me about how we played. What concerns me more is my discipline to make the right calls, get my team in the right position, make sure when I’m on the backline that my team knows what they’re doing and when we’re doing it, and just communicating better.”

Killian Hayes has missed all three preseason games now with a sore hip.

“I’d love to see him. He’s doing well. He’s rehabbing,” Fernandez said. “He’s been just working on getting back and getting right. And I’d love to, but we’ll assess him when we get back and see what we can do.

“We’re not going to rush him, because his health is our priority, same as every other player. So it’s no need to risk. He’s done a good job. … We have our own evaluation on him, and we’re very happy with him.”

The Nets haven’t decided to fill holes with their open two-way (backup center, backup point guard) or use it on the best available.

“Yeah, that’s gonna be a discussion between myself, [general manager] Sean [Marks] and his team,” Fernandez said. “Once we go through these games, we’ll sit down and we’ll discuss how we feel. I like the guys that have been here for now. And that’s all I can say at this moment.”