No that would be trading the player itself, as a rookie contract firstrounder is immediately guaranteed.
anyways, depressing confirmation from the man himself
You cannot make a trade which leaves you without a first
round draft pick in consecutive FUTURE years. Your scenario
is correct -- each year, you could trade away that summer's
first round pick. You may not have a first round pick for
ten years, but as long as you were never without consecutive
future picks, it's okay. So when a team is considering
whether they can trade a future draft pick, it does not
matter what happened with any previous pick.
So a team can trade their '02 pick OR their '03 pick, but not
both. They can trade their '03 pick OR their '04 pick, but
not both. Etc.
Also, the draft pick they have doesn't even have to be THEIR
pick. A team could trade their '02 and '03 picks as long as
the same trade or an earlier trade brings them somebody's
'02 or '03 pick.
Hope this helps,
Larry Coon