Francona...lol. Not only do his accomplishments not belong anywhere close, but the level of strategy from a baseball manager compared to these others?
Yes, Bill Belichick is the greatest coach and coach/GM in Boston sports history and maybe in all of America.
Red Auerbach is a remarkable figure and certainly would also rank among the greatest in any region, but this was an eight-team league that generally retained the same hall of fame players each year. Belichick flips the roster every 3-4 years and competes against 31 others in a salary cap league where parity vastly effects every other team; it's like he's immune to gravity.
John Wooden would be very worthy of mention as well, considering the four-year turnaround of college players and the constant rebuilding. The only issue is that is college sports, so I don't know if it qualifies. I'll still take Belichick, though.