Reference Marcus Trice, who we recruited by us last year as a 5'8" corner--and after he committed to OU, ended up a four star. Of course, he's also in OU's two deep at safety now...
They re evaluate players all throughout the year. C.J. Morgan was a 2 star player, but he ended up being a 3 star. Adrian Bennett was the same way. I'm guessing that Trice was 5.7 3 star player, which means he was barely not a 4 star player and after re evaluation he was seen as a better player than others and was viewed as a higher ranked player.
The ranking system ranks prospects on a numerical scale from 6.1-4.9.
6.1 Franchise Player; considered one of the elite prospects in the country, generally among the nation's top 25 players overall; deemed to have excellent pro potential; high-major prospect
6.0-5.8 All-American Candidate; high-major prospect; considered one of the nation's top 300 prospects; deemed to have pro potential and ability to make an impact on college team
5.7-5.5 All-Region Selection; considered among the region's top prospects and among the top 750 or so prospects in the country; high-to-mid-major prospect; deemed to have pro potential and ability to make an impact on college team
5.4-5.0 Division I prospect; considered a mid-major prospect; deemed to have limited pro potential but definite Division I prospect; may be more of a role player
4.9 Sleeper; no Rivals.com expert knew much, if anything, about this player; a prospect that only a college coach really knew about