He knows how much the Michigan defense struggled the past three seasons. But he also told himself before taking the job that he wasn't going to look at a lot of film from 2010.
"The only reason I was looking at film was to see players, not schemes," said Mattison, who was defensive coordinator with the Baltimore Ravens. "It's not my place to judge what happened before. I've always taken that approach. I was hired to do a job, and my job is to get the defense to play up to Michigan standards."
Mattison's ability to do that will determine if Michigan is able to return to the bowl business and perhaps be a dark horse in the Big Ten Legends Division under first-year coach Brady Hoke.
It has been a while since the Wolverines were a serious Big Ten title contender, last winning a share of the crown in 2004. That was under Lloyd Carr, who retired after the 2007 season. Rich Rodriguez took over, and Michigan sank to depths it hadn't experienced since the pre-Bo Schembechler days in the 1960s.
At the root of Rodriguez's problems was a horrible defense, one that ranked last in the Big Ten in total defense (450.8 ypg), scoring defense (35.2 ppg) and pass defense (261.9 ypg) last season.
After Hoke was hired away from San Diego State, he reached out to Mattison to run the defense. The duo has a close relationship that dates to their days on the Michigan staff as defensive assistants. Mattison was an assistant in Ann Arbor from 1992-96, while Hoke was there from 1995-02.
"I'm not a big phone guy, but Greg and my brother [Jon, the Chicago Bears' secondary coach] are really the only guys I talk to on a regular basis," Hoke said Friday at Big Ten Media Days. "Our friendship and familiarity with each other began a long time ago. …
"We are two defensive-minded guys and would share some ideas and talk about the game a bit."
Mattison immediately ditched Michigan's 3-3-5 scheme and installed a more conventional 4-3. The alignment will, theoretically, maximize a strong line.
"We will be a four-man front," Mattison said. "And I always believed a strong defense begins with the guys up front. You have to have a great defensive line to win in any league. You have to play with unbelievable energy, have great effort on every play, which means probably rotating more than what has been done in the past. The new guy who comes in may not be as good but plays as hard as he can."
The leader up front will be senior tackle Mike Martin, who will be one of the best defensive players in the Big Ten.
"I am not much of a vocal leader," Martin said. "I like to lead by example. I did get into some guys' faces. We all are doing a great job leading as seniors and upperclassmen.
Oh, my, avert your eyes
A look at the past three seasons for Michigan's defense, with its yards-per-game and points-per-game averages, as well as its rank in the Big Ten in that category.
"[The new scheme] is different in a lot of ways. It is a lot of fun to have four guys up front. There are a lot of new things to learn and we have been improving. We installed a lot and observed a lot."
Personnel still may be an issue for Mattison. The linebacking corps has had issues, and that unit's struggles were a major reason the defense was so bad in 2010. Staffers are excited about redshirt freshman Jake Ryan, and sophomore Cameron Gordon was shifted from safety to add athletic ability and speed. Returning starter Kenny Demens, a physical 250-pound junior, looks like a playmaker inside. But more help is needed.
The secondary also bears watching. The staff moved Carvin Johnson from linebacker to free safety, and it's hoped the return of cornerback Troy Woolfolk will be a boost. He missed last season with a dislocated ankle suffered in late August. Cornerback J.T. Floyd also is back after being sidelined for the season in early November with an ankle injury.
"I couldn't say this is one area better than others," Mattison said. "There are players in each group that have a great deal of talent. And there are others who must prove themselves and step up.
"I have been very proud with how this defense has bought in. I think, to a man, each wants to be Michigan football players. We talked a lot that the bar to be a Michigan defensive player is very high. A lot of times you think you are at a level that's acceptable, and it's still not. We have work to do, but I like our potential."