I'm a Niners fan and the same thing happened to them a few years back. Matt Leinert was "supposed" to come out as a junior, but he knew that the Niners had the first pick and I think he got cold feet. (Leinert "said" he went back to try to earn a national title, but I don't believe that for a minute.)
The net result, of course, was that the Niners drafted that bum from Utah -- Alex Smith. I wanted Aaron Rodgers, but no one in the Bay Area listened to me.
It's not easy having the first pick. In all seriousness, we need a competitive Lions. I wish them good luck this April.