Grading every Michigan position group, including coaching, after the first period

Michigan coach Jim Harbaugh says John O'Korn played great and saw the whole field in the 28-10 win over Purdue on Sept. 23, 2017 in West Lafayette, Ind.Nick Baumgardner, Detroit Free Press

(Photo: Brian Spurlock, USA TODAY Sports)There's no opponent this week and nothing to predict.

But, Michigan has completed one third of its 2017 football season. We'll say the Wolverines are at their first period intermission.

So, how about some reflection? Here are position — and coaching — grades through the first four weeks.

Quarterbacks

The most interesting position group on the field got that much more interesting last week when Wilton Speight was helped off the field and John O'Korn took over to lead the…