The 34-year-old Brazilian was injured in the first quarter of Sunday's Game 4 win over the San Antonio Spurs.
The 34-year-old Brazilian was injured in the first quarter of Sunday's Game 4 win over the San Antonio Spurs, hobbling off after just two minutes.
"The Rockets medical staff is currently reviewing treatment options," the team said in a statement.
Nene's absence is a blow to the Rockets as they prepare for Tuesday's Game 5 with the series finely balanced at 2-2.
The 6ft 11in (2.1 meter) forward has averaged 10.8 points and 5.3 rebounds per game during the playoffs.
Rockets star James Harden called on Houston to rally around following Nene's injury blow, with Montrezl Harrell a likely back-up option at center despite only playing 18 minutes in the postseason.
"He's a big part of what we do," teammate Harden said of Nene.
"Guys have to step up. It's an opportunity for guys who don't play big minutes and for guys like Montrezl who haven't really played and might get some opportunities. Whoever it is, we've got to try to fill that role."
Nene joined the Rockets last year after a four-year stint with the Washington Wizards which followed a decade with the Denver Nuggets.