As to the Rookie Contracts Cap, the NFL gives each team a certain amount of cap room every year to sign their rookies and does not count such rookie year deals in the team's salary cap. Thus, Taylor Jacobs' salary was not counted against the Skins cap last year, but it will this year.
It is determined by the number of picks you have and how high those picks are.
Here's a decent article from last year about how it all goes down.
http://espn.go.com/nfl/columns/pasqu...n/1547910.html