I imported a series of players bc the Create Player functionality is broken unless you are creating a QB. I can see some of these players under "Player Search - View All", with an "N/A" under Team. These players are not available as Free Agents but appear to be in some kind of limbo where they can't be signed.

Make sure when importing players that they don't have player id's, and that their team id is 0 so they get dropped into free agency. I'm not sure why they wouldn't be available to sign once they're in the game though.

Yeah I found it strange, and I've only seen it once, but I'll use the player id method you suggested. Thanks