Reviewing Sleepers from the 2009 Book - Minor League Ball#storyjump:
"One of the things I try hard to do in the book each year is to get ahead of the curve on prospects, to pick out players who might not have a lot of publicity heading into the season, but who could emerge as top prospects if things go right. In the book, I put the tag 'Sleeper Alert' next to such players. I don't put this label on a guy if they were a hot prospect that everyone knows about: the point is to notice them before they are big names."
Hey, I hit on Derek Norris before that!