General manager Billy King made the announcement Thursday. Lopez was injured in the first half of Wednesday night's preseason game against the New York Knicks.
King said he had no choice but to be comfortable with the roster he's got.
"I'm gonna do my job and look at the options, but they're not going to stop the season," he said. "We're going to be in Washington on the 26th at 7:05 tipping off. And we've got guys that are professionals, that's their job -- when somebody goes down they've got to step up. But, you know, I'll do my job and look into try to help the roster at the right time. If I can do it before we start then that would be great."
The 6-foot-11 Okur will make $10.8 million this season, in what is the final year of his contract.
The recovery time for an injury like Lopez's commonly is four to six weeks. Given that time frame, he would be on track to return sometime in February, not including any potential setbacks.
"I don't look at it like it's always something. I look at it as another opportunity," coach Avery Johnson said. "We're definitely disappointed. I had a long talk with Brook last night. He is not in great spirits but we tried to lift his spirits to let him know that, hey, this is a little bit of a setback but he could definitely have a big time comeback.
"Hopefully, once we get through with the surgery and get back to rehabbing and he can heal up and we can get him back at some point this season."
By comparison, Lopez's teammate, second-year small forward Damion James, suffered the same injury last season and was sidelined for about 10 weeks. In 2006, Los Angeles Lakers center Pau Gasol, a fellow 7-footer, also suffered the same injury when he was with the Memphis Grizzlies and missed three months. Gasol later returned to his dominant form.
"It's definitely devastating," Nets point guard Deron Williams said Thursday. "Brook's a big part of our team. But there's one thing you learn in this business -- you can't control injuries. From what I understand, it's not that severe, so hopefully he'll be on the court soon."
"I've seen star players go out before," Johnson said. "And the main thing is we have to play with a lot of urgency. We've got to play, nobody's going to give us any sympathy. We're not asking for any. We're missing one of our top two players, that's a fact. But we're going to suit up. We're going to be ready to go in Washington and hopefully give ourselves a chance to win."
Lopez averaged a career-high and team-best 20.4 points per game last season, and was intent on improving his career-worst average of 6.0 rebounds. In two preseason games against the Knicks, Lopez had 20 rebounds and looked to be well on his way to accomplishing that goal.
"Everybody is going to have to step their game up a little more," Williams said.
Mike Mazzeo is a regular contributor to ESPNNewYork.com. Information from ESPNNewYork.com's Christopher Hunt was used in this report.