Mel Kiper's debut 2012 mock draft - NFC North Blog - ESPN. All four NFC North teams are discussed. For the Green Bay Packers, it's Illinois DE (who Kiper considers a LB) Whitney Mercilus. More on him from CBSSports.com:
Mercilus had a remarkable year for the Fighting Illini, tying Simeon Rice's single-season record and leading the nation with 16 sacks. He also forced nine fumbles on the season, breaking Illinois and Big Ten records and ranking as the second-most in NCAA history. His 22.5 tackles for loss in 2011 led the Big Ten, rank second in the nation and third in the Illinois record book.
He's a big time playmaker which is something that any defense can use. At 6-4 and 265 lbs. he's a candidate to convert to outside linebacker. I'm sure the Packers will take a look at him and see if he can drop back in coverage. If he can't play in coverage, then he'd be a bad fit for the Packers.
There are some success stories, like Clay Matthews, of college defensive ends that became great 3-4 outside linebackers. But there aren't a lot of them. This is a position to tread carefully on.