Plus they've done everything they've done this season while missing significant time from arguably their 3rd and 4th best players, with DeMarre Carroll playing in only 23 games and possibly out for the season and Jonas Valanciunas also missing 17 games.
Think about how good we'd feel about the Celtics 33-25 record if Jae Crowder went down for the rest of the regular season in Decemebr (but with a playoff return hopeful), and that Marcus Smart injury still happened. And the Raptors are 6 games better than that with a likely top 10 pick coming next year.
Of course that rosey outlook could all change if DeRozen walks in free agency, but I doubt he's leaving that bromance he has going on with Lowry.