HD to SD encoding (slighty Off Topic?)

Hopefully somebody can help. I ma going to be given a Quicktime (Pro Res codec I believe) that is HD frame size (1920x1080). I'm assuming it will Progressive. Its at 25 fps AFAIK

Of course I have to produce a SD encode from this source. I have Compressor with the Cinemacraft plug in.

So my question is can I just "feed" the Quicktime to Compressor using one of my Cinemacraft presets for 16x9 encodes (possibly changing it from Interlaced to progressive) or do I need to do some kind of frame conversion in either FCP or Compressor first and create a new source to "feed" to compressor to create the encode...

Of course I'm up against time wise as the person who created the high def file was supposed to create the SD encode but it came out wrong...

I'm hoping somebody like Alex will chime in on this (as I'm guessing he's probably dealt with this scenario before)

Any help greatly appreciated

Steve