Long-time UMich fans may be familiar with Trevor Pryce. He played a couple years at Michigan in the mid-'90s before transferring to Clemson. (I'm hazy on what prompted the move.) He was a 1st-round pick of the Broncos and (as you'll see here) has had a long NFL career. This article contains his thoughts on retirement:
Not something I'd post mid-season, but it seems OK for now.