OPP ...
I thought the initial "contract" was 5 years ...
If my memory serves me correctly, the "Rule 5 Draft" pertains to minor league players who do not move onto a 40 man roster at the end of their first 5 years, and allows other teams to "draft" them. To protect themselves from losing a good prospect, the MLB team will "buy the contract" of their minor league player and put the player on their 40-man rosters so that other teams can't take them after their 5th year. The player is also afforded some benefits that he wouldn't have in the minors (with the Players' Association, etc).
We had a friend who was placed on his team's 40 man roster last fall so he wouldn't be nabbed by another team.
ShapsMa