The way the keeper system works is if I have a player on my roster at the end of the year that was drafted in the fifth round I would give up my fourth round pick to keep that player the next year. So this year's fifth rounder is next year's fourth rounder (If you decide to keep him the year after it would be a third rounder). So yes, this means any first rounders from this year wouldn't be keeper eligible, that adds a degree of strategy and it is so everyone can have a chance at the most popular and perhaps 20 best players. They can't be kept forever by the same team.

Another thing to add to that is that if someone trades a guy to you who was drafted in the tenth round and you decide to keep him then it is as if you drafted him in the tenth round. Any questions at all please feel free to post them on the message board. Someone else may have the same question as you.