Brandon Graham had 10 sacks last year at defensive end. Donovan Warren is a three-year starter at cornerback. But the biggest key to Michigan's revamped defense this year?

Sophomore nose tackle Mike Martin.

"Mike is a guy that, he’s probably as important a piece to our defense as anybody we have over there," Rodriguez said. "He's a guy that had a great summer, very explosive, and we need him to play well and we need him to stay healthy."

Coming off a standout freshman season in which he had 20 tackles and two sacks, Martin's value to Michigan cannot be understated.

He's the only experienced nose tackle on a roster thin on defensive linemen, and in Michigan's new three-man alignment he's being counted on as a pass rusher, run clogger and anchor up front.

Rodriguez said Martin should play 45 to 50 snaps a game this year, and expressed no doubt the former state-champion wrestler can be an effective zero technique at his current 6-foot-2 and 292 pounds. (By comparison, William Campbell, Martin's true freshman backup, is 320 pounds.)

"He's big enough to play anywhere," Rodriguez said.

Linemate Ryan Van Bergen agrees.

"Mike Martin is much improved," Van Bergen said. "He is very talented for a young guy. He put up some amazing numbers as a freshman and as a true sophomore he’s only gotten better. We really expect him to carry a big load there at nose guard for us."