Maybe the top pick is locked in. But after that, FA is bound to reshuffle things.
Despite the mythical BPA, the reality is that teams draft mostly for need (whether they should or not is open for opinion) unless they are loaded everywhere (doesn't happen much).
Even teams that preach "BPA" pick a guy that it just so happens is a position of need..... at least they do in the early and mid rounds. Admittedly that need might be for the following season and not the current.
So if the right FA can fill a need, the guarantee is bigger of that position/player being successful than any pick you can take in the draft. And, that FA can plug right in and start.
