Brooklyn Nets guard James Harden is out indefinitely after sustaining a setback during his rehabilitation from an injured right hamstring, the team announced Tuesday.
"We're back to square one," Nets coach Steve Nash said. "He will be back when he's back. It might be the play-offs. It might be sooner."
The 31-year-old was re-injured during an on-court session, according to the team. He underwent an MRI exam Tuesday to learn the severity of the injury.
Harden is averaging 25.4 points, 8.7 rebounds and 11 assists in 34 games since joining Brooklyn early in the season from the Houston Rockets in a three-team trade.
He has not played since April 5, when he left after less than five minutes of action against the New York Knicks.
Last weekend, Nets general manager Sean Marks spoke optimistically about Harden's return.
"James is progressing well," Marks said. "He's looking forward to having at least one or two more play days, which means he'll play four-on-four, five-on-five with the group in practice. And then hopefully if things go smoothly, he'll be out and joining the guys in a game."
Harden is a nine-time All-Star, three-time NBA scoring champion and the league's 2017-18 MVP.
He was considered a strong candidate for this season's MVP honour before his injury, keeping the Brooklyn Nets in the running for the top seed in the Eastern Conference while both Kevin Durant and Kyrie Irving missed games.
On Tuesday night it was Irving's turn to lead the team in the absence of Harden and Durant, who is now also day-to-day due to a thigh contusion he suffered in the first quarter of Sunday's game against the Miami Heat.
Despite again missing two of their 'Big Three', Brooklyn still got the win in New Orleans against the Pelicans 134-129.
Irving topped the box score for his team with 32 points, Joe Harris had 24 and the Nets role players - Griffin, Green, Shamet, Brown, Luwawu-Cabarrot - all scored in double digits.
Steve Nash's team now travel to Tampa, Florida to face the Toronto Raptors as they seek to reclaim first place in the Eastern Conference from Philadelphia 76ers, who themselves take on Phoenix Suns at midnight.