BOSTON — Andrew Bynum is set to start Game 5 of the NBA Finals tonight. The only change in the Lakers’ active roster is that backup center DJ Mbenga, a possible Bynum replacement if his injured right knee isn’t sound, is out and forward Adam Morrison is in. Lakers coach Phil Jackson said the team never talked about sending Bynum home early so he could get more rest and treatment in the hope that he would be better for Game 6 on Tuesday. Bynum had fluid drained from his knee very early Friday morning.