It sounds good that the Bills would bring him back on a cheap contract as a depth CB, and the timing would need to be after the FA allocations are determined. But, the thing is, even depth CBs have to play, and Tre just looks slow. Possibly this was because he wasn't integrated into the Rams' or Ravens' system and was still thinking about where he needed to be, or maybe he just got injured too much and old.
Tre is where Douglas will be in a year or two. Paying Douglas a lot just to watch him slide into his slow-running 30s doesn't make sense.