It might be time to worry in Boston. The Celtics have lost four straight and have yet to defeat a single winning team. Their four wins have come against the NBA's worst team (the Washington Wizards, who the Celtics have beaten twice), and the two teams tied for the second-worst record (the New Jersey Nets and Detroit Pistons).
I'm not asking the Celtics to beat all of the Mavericks, Bulls and Pacers. Just one of them. That loss to Indiana was a brutal indicator that this team is toast. Boston has a -2.5 efficiency differential against a subpar strength of schedule. Yikes.
It's not necessarily time for Celtics fans to abandon any hope of making a postseason run, but a better start surely would have been appreciated.