Well, one point to consider is that Minnesota wasn't losing games en masse or not playing well. They lost a game by 4 points on the road to a top 20 team while surrendering less than 300 yards of offense. Yes, they performed poorly against Wisconsin, but that was the last game of the year. Yes, they didn't rush the passer particularly well for most of the season, but on the whole the defense was a top 25 unit the entire year by most metrics. Why burn redshirts when you can allow kids to get bigger, stronger, faster, and more familiar with the system while your defense performs well enough to win?