Actually, second rounders have more value than late-first round picks because guys taken in the second round are not given guaranteed slotted deals. A failed second rounder can be cut with no cap hit. A failed first rounder eats up cap space.
I suspect that, unless the Blazers see someone they absolutely love slide into the latter stages of the first round, they will end up trading a most of those second rounders for future picks. If someone does slide, they might be able to put together a package to move up as high as the #18-#22 range and snag an extra first rounder.