ANN ARBOR, Mich. -- Michigan defensive coordinator Greg Mattison sat his players down in the visitors' locker room Saturday night at Ryan Field. It was halftime, and the Wolverines trailed 24-14, obviously not the best 30 minutes for a defense that had garnered praise for its turnaround from a year ago.
In Michigan's first five games, defensive lineman Ryan Van Bergen said, the changes Mattison had made had been small and simple. This was going to be a big change in a small amount of time.
Michigan had been hurt by Northwestern's run option. The Wildcats had also unexpectedly run more bubble screens than anticipated, leaving Mattison about 20 minutes to overhaul his plan.
"It was a pretty serious thing," Van Bergen said. "To bump all the linebackers back the way we did, but it was successful."
Michigan pulled its linebackers off the line of scrimmage more to allow them a split-second more time to read where Dan Persa or Kain Colter would try to run an option. It also caused more traffic for receivers running short routes over the middle.
And like it has through six weeks this season, No. 10 Michigan had success.
Michigan has dominated second halves this season, outscoring teams 114-21. The Wolverines have taken opposition strengths -- in this case the option and bubble screens -- and eliminated them. But the changes were more pronounced Saturday. What Michigan prepared for during the week was different than what Northwestern used, because of the season-ending injury to Wildcats running back Mike Trumpy against Illinois.
But to understand Michigan's success this season is to look at what Mattison and offensive coordinator Al Borges have devised after the first quarter and put into full usage after halftime.
"We see something different pretty much all the time with how people want to defend us offensively and defend Denard [Robinson]," Michigan head coach Brady Hoke said. "Al does a tremendous job, they all do a tremendous job, of getting together and talking during the course of a game, the first half, putting their ideas down and making the appropriate adjustments and changes.
"The same things defensively."
Michigan didn't do this as well with former coach Rich Rodriguez. Through six games a season ago, the Wolverines outscored opponents 102-75. By the end of the year, they still outscored opponents in the second half, 199-180, but those numbers were buoyed by the strong start. By mid-October, opponents had started to adjust better through the Big Ten.
Through last season's last seven games, including a Gator Bowl loss to Mississippi State, opponents outscored Michigan 105-97 in the second half.
The biggest statistical disparity for Michigan has been the adjustments throughout the first half. This season, Michigan is outscoring teams 79-19 in the second quarter through six games. In the same span last season, opponents outscored the Wolverines 69-49 in the second.
The evolution of adjustments for Michigan is something that starts early -- both Mattison and Borges have said they'll make changes throughout the first half -- and continues through halftime. In each quarter this season, the Wolverines' defense has gotten progressively better in points allowed, dropping from 35 first-quarter points allowed to 19 in the second, 14 in the third and seven in the fourth.
After slow first quarters, the offense has been consistent, scoring 79 points in the second, 52 in the third and 62 in the fourth.
"Once we get into that game and the second half starts and everything starts working you go, 'OK, we're going to roll,' " senior center David Molk said. "Now that it's happened a couple times and we understand what he's doing and trust him, we just go out there."
Seeing it work gives Michigan more confidence each week as Borges and Mattison institute their changes. They've worked before, so they feel they'll work again.
So far during Michigan's 6-0 start, not much they've changed has gone wrong.
Second That Emotion
If you count the 14-0 third quarter against Western Michigan before thunderstorms brought a premature end to the game, Michigan is second in the nation in second-half point differential.
Michael Rothstein covers University of Michigan sports for WolverineNation. He can be reached at email@example.com or on Twitter @mikerothstein.