Rookie Chris Copeland says his left shoulder isn’t “100 percent’’ but is aching to help the Knicks moribund offense tonight in pivotal Game 6 at TD Garden. Mike Woodson confirmed Copeland is in line to play tonight with Steve Novak out with back spasms. Copeland started Game `1 but, as Woodson noted, “looked nervous.’’ “It’s still not 100 percent, but doctors told me it will be a few weeks before that,’’ Copeland told The Post at Suffolk University at the morning shootaround today. “But I’ll be fine. I’m ready to play. I want to play.’’ Copeland played just 12:48 in Game 1, starting to fill the hole left by injured Pablo Prigioni. He was 0 for 3. He has been a DNP the past two games after playing just garbage time in Games 2 and 3.Copeland's shoulder popped out in the regular-season finale vs. Atlanta and he has taken a couple of cortisone and painkilling injections.