[Dirtyskin21]

Well coaches always work out the better players because that helps them be able to better evaluate other players talent in the drafts to come. You can see every differen't type of player and their style, and in my opinion that would help you be able to scout/draft players better in the later rounds when you have worked out the better players.

This is just my opinion but I would think this is why, plus you NEVER know when a player will drop to you or what not.