SAN ANTONIO — When David Nwaba crumbled to the court at AT&T Center late in Thursday’s 118-105 loss to the Spurs, he took the Nets’ defense with him. Nwaba suffered what appears to be a torn right Achilles tendon, an injury that almost definitely will be season-ending.

Nwaba is flying back to New York with the team to be examined, and he likely will have surgery Friday.

It’s horrible news for both the Nets and Nwaba, their latest success story.

“I just wish him the speediest recovery,” coach Kenny Atkinson said. “There’s no guy on the team who does things more perfectly in terms of preparing for a game, preparing for a season. You just feel ill when you think about it.”

From Jeremy Lin two years ago to Caris LeVert last season, the Nets have seen far too many gruesome season-ending injuries. But they never get used to them.

“That’s just bad, man. Great guy, worked hard to get in the league, been playing the best he’s played since he’s been in the NBA,” Garrett Temple said. “For him to go down like that, it’s just tough. My heart goes out to him, prayers go up for him.

“Everybody walked up to him when we walked in here and told him what they wanted to say to him individually. Then coach came in and said what everybody was thinking: We’re not really worried about the game. Right now we’re worried about our brother.”

When Wilson Chandler returned from his suspension for performance-enhancing drugs, the Nets released 16th-man replacement Iman Shumpert and went with the younger Nwaba. They could turn back to Shumpert now once a league-designated physician certifies Nwaba is done for the season.

“You just keep preparing. It’s next man up,” Spencer Dinwiddie said. “Odds are we’ll probably get Shump back, which will be cool. But you never want it to happen in this way, especially with Dave catching a rhythm, playing so well and being so dynamic. It’s not cool, it’s not fun.”

The Nets have until Jan. 15 to apply for a Disabled Player Exception, though there are limits on who can be added. According to former Nets assistant general manager Bobby Marks, they can sign a player to a one-year deal, trade for a player in the final year of his contract, or place a waiver claim on a player in the final year of his contract.

What they can’t do is use Nwaba’s injury — along with those to LeVert and Kyrie Irving — as an excuse to capitulate.

“We don’t have a choice. We’re [28] games in. What are we doing to do, not play the other 54?” Dinwiddie said. “We literally have zero choice but to dig in and next man up and all that stuff.

“If this was game 81 or game 80 and we aren’t making the playoffs, we could be like, ‘Oh, [screw] it, who cares, the season’s over.’ But we’ve got 50 games left.”