Not giving an older player with an already existing major injury history a multi-year deal would be a good first step from Douglas to show that he's learned from his past mistakes.
We'll offer him a 3 year deal with a massive signing bonus and assume the tackles are set. EDGE/Safety in the first round.
I think a one year deal with a player option for a second that activates based on snaps wouldn't be the end of the world.
I also think there's a decent chance that he doesn't want to come here, or he just retires. The poor guy has been through a miserable time with botched operations on his knee, he might well decide that the last thing he wants to do when he's finally through all the medical trauma is risk MetLife turf destroying it again.