18 keepers is a lot. I've played for years and never been in a league with more than 6. Anyway, where'd you finish last year? What kept you from being higher? Rasmus is a nice player but can you give up Upton's steals? What if he hits 24 HR's as he did in 2007? He also gets on base a lot (good OBP) with his walks negating his K's. With 234 keepers in your league, your extra 1st round pick is not too valuable.

What kind of players are availabe in the first round? I've heard 2 so call experts call Rasmus the rookie of the year next year even though he had a down year in AAA this year. If you can get Rasmus and another pretty good player or another top notch prospect like say LaPorta, Price, Teagarden or Gamel or something like that then I'd say do the trade if your main thought is for the future. Upton is losing value for next season by losing 2B eligibility.