I thought things were odd with Calvin the last few games. It was like he was taking it all in and wanting to collect a few souvenirs on his way out. I thought it was because he was expecting to get cut or traded though, not that he'd retire.
The retirement talk has apparently been going on for a while now. One of the beat writers (O'Hara, I think) was on 105.1 this morning saying that several of his teammates have known this was coming since about week six or seven, and that none of us realized how physically beaten up he's been the last few years. Knees, ankles, and hands in particular. CJ has made around $100mil and is getting married this offseason, and they were speculating that he watched the concussion movie and decided it might be time to hang 'em up now. They say it is completely different than when Barry did this at roughly the same point in his career though. They felt that the organization knew this was likely coming.
We'll see... I hope this isn't it for Calvin. I'd love to see him play a couple more years in Detroit, even if it means him sitting out and healing up a bit more than he has. Probably unlikely given the financial impact that would have though.