Getty Payton Pritchard #11 of the Boston Celtics talks to head coach Joe Mazulla As things stand in the betting world, the front-runner for the NBA’s coach of the year award is not Boston Celtics coach Joe Mazzulla, even after his team has eclipsed the 50-win mark despite playing the first four-plus months without star Jayson Tatu m, who tore his Achilles tendon in last year’s playoffs. It’s JB Bickerstaff of the Pistons who leads the way according to most sports books , and that’s probably a