Marcus Camby was on the plane for the Knicks' three-game road trip, but when he will play again because of his sore left foot remains a mystery, as his season is going from bad to worse. Camby didn't dress for Sunday's game against the Suns due to his foot, and coach Mike Woodson doesn't know if Camby will be available during the trip. Woodson never had mentioned Camby's foot pain, even before Sunday's game, and yesterday acknowledged that has been part of the reason Camby's playing time has been reduced. According to a source, Camby has undergone tests on his foot. That Camby's foot remains sore despite an extreme lack of playing time calls into question whether his injury is chronic plantar fasciitis. "He's going through some treatment,'' Woodson said. "I don't know the extent of it, but it's been bothering him. We'll continue to treat him and wait patiently until he comes back.'' Camby has looked slow when he has been on the court. He has played in just six of the team's 16 games, averaging 7.7 minutes. Rookie forward Chris Copeland, a surprise to make the team out of training camp, had even slid ahead of him in the rotation.