Photo by Tim Heitman/Getty Images Joe Mazzulla, Boston Celtics The Boston Celtics are second in the Eastern Conference with a 19-4 record. Interestingly, we’re yet to see them have a run of games with a fully healthy roster. Joe Mazzulla’s team can still take things to another level, which should be frightening for opposing teams considering their hot start. Nevertheless, every team is always looking for ways to improve. For the Celtics, that means improving the bench rotation somewhere between