Sounds like Courtney Lee was not upset about losing his starting job to Avery Bradley.
Lee finding a comfort zone - Boston Celtics Blog - ESPN Boston
Though he has filled in as a starter at times this season, Lee said coming off the bench gives him the opportunity to observe the game first and better prepares him for how to play when he enters.
"Just being able to watch the game and see how the flow of the game's going and seeing what areas that we're lacking on, whether it be the defensive end or the offensive end if it's energy or pushing the tempo or getting out and running," Lee said of observing from the bench first. "You can see all those things. You're pretty much the coach's eyes over there. You can see it. As far as when you're playing, you don't notice a lot of things. So you can see it and then when you get in you can try to make those adjustments."