Hornets coach Monty Williams did not say how severely Gordon's right knee is hurt:
"He's going to be out. The way I understand it, he's going to be out indefinitely until we get some more clarity on what's going on so I don't have to answer these questions every day and give you guys the update. We'll just go from there."
Right knee pain kept Gordon out for all of training camp.
Gordon, 23, appeared in just nine games last year during his first season with the Hornets. Gordon averaged 20.6 points per game in limited time.
The first-round draft pick in 2008 was traded to the Hornets from the Los Angeles Clippers last December. The Hornets acquired Al-Farouq Aminu, Chris Kaman and a draft pick (which turned out to be Austin Rivers) for guard Chris Paul.
In four seasons in the NBA, Gordon averages 18.2 points per game and 3.3 assists per game. He started 64 games as a rookie with the Clippers.
Rivers, the 10th overall pick in the 2012 draft, is expected to start in Gordon's place against the San Antonio Spurs on Wednesday night.