Grading the Celtics at midway point

The Boston Celtics stumbled into the midpoint of the 2012-13 season riding a four-game losing streak that dropped the team one game under .500 (20-21) and left it six games back in the Atlantic Division and clinging to the eighth seed in the Eastern Conference.

This isn't what Boston had in mind when it reassembled much of its core and revamped its bench during the offseason. We break out our red pens and assign grades for the first half of the season and, in the process, it becomes painfully clear why this team has underperformed:

(Players sorted by total minutes played)