If you were looking for some sort of timeline as to when Greg Mattison might retire, you've got at least a few years before your can get your fret on:
Greg Mattison's three-year contract extension will keep him as the
#Michigan defensive coordinator through the 2016 season.
Four more years, four more years, four more years. At least. With recruits chattering about how the guy seems 25 he may find a wellspring of Red-like longevity in there and keep going.
At the very least, Michigan won't have to worry about a major staff transition until after a couple seasons of Hoke's program running full-tilt like Hoke wants to run it.