Chauncey Billups didn't play last night for the Knicks, and his availability for tomorrow's do-or-die Game 4 is in doubt, too. "Obviously if it was close, I would play," Billups said before the Knicks lost, 113-96, at the Garden last night to fall into a 3-0 hole to the Celtics in their first-round playoff series. Billups missed his second straight playoff game because of a strained tendon in his left knee. The veteran point guard wouldn't venture a guess on his odds to play tomorrow, and he couldn't promise he would be able to return even if the series went to seven games. "I think there's maybe a chance, but I don't know that to be 100 percent sure and true," Billups said. "But I can just kind of go day to day and see how it goes. "Hopefully the cortisone hasn't kicked in yet and I can make a jump here soon in a day or two. That's me. I'm just praying for a miracle." Billups hurt the knee when he drove against Jermaine O'Neal and crashed to the court in the final minute of Game 1 in Boston. He said he's unable to jump or even put pressure on the knee. "It's a tough injury," he said. "Walking around, I'm fine now. But as you see in the series, there's not a lot of walking being done." Billups went to the Knicks' training center in Westchester County yesterday morning to determine if he would be able to play last night, but said the physical tests didn't go smoothly. He tried a variety of exercises in the pool as a facsimile of what he would have to do in a game, but failed those tests.