Harden was conducting an “on-court rehab session” on Monday when the setback occurred, according to a team statement.
The Nets said Harden had an MRI on Tuesday and will remain out indefinitely.
“We’re back to square one,” Nets coach Steve Nash said. “He will be back when he’s back. It might be the playoffs. It might be sooner.”
Harden has missed the Nets’ past six games. He last played on April 5 against the New York Knicks when he logged just four minutes of game time before suffering a strain. Harden had been dealing with some hamstring tightness before exacerbating the issue against the Knicks.
Harden is averaging 25.2 points, 8.0 rebounds and 10.9 assists per game for the Nets.