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?I too don't know anything about how often starters are replaced but I do recall two recently on our D team. Neither Cashman nor Coughlin started in the first game yet sure did take over during the season. I just don't know why a coach would want to keep a better player on the bench while his team is losing games or not playing well. Maybe early in the season while the new talent is still too raw, but after fifty, sixty, seventy practices and 10, 11 or 12 games?