Hall appeared in 12 games for the New York Giants in 2016, recording 31 combined tackles and intercepting one pass. Pro Football Focus graded him as the 44th-best qualified cornerback (75.9) in the league.
The 32-year-old has never been the same player since suffering an Achilles injury that limited him to five games in 2013. Prior to the injury, he was consistently one of the better corners in the NFL despite never reaching the Pro Bowl.
Hall successfully recovered from an Achilles issue in 2011, but the second proved to have more serious long-term consequences. He never regained the athleticism he possessed before going down in 2013, and as a result, his pass coverage has failed to reach elite status again.
That's not to say Hall's days as an NFL-caliber defensive back are completely over. However, his ceiling is much lower than it was during his prime years with the Cincinnati Bengals.
The back half of the 2016 campaign offers a reason for optimism around Hall in 2017 and beyond. He began the year as a slot cornerback for New York but played increasingly more after returning to action in Week 13.
In an interview with NJ Advance Media's Dan Duggan, Hall expressed a willingness to play a variety of roles:
"I move around a little bit. I like the jack-of-all-trades deal. I've always liked to do other things, different positions. I remember being in Cincinnati telling them to do that. That didn't work out. But I enjoy it. I would say my position now if I had to pick one would definitely be safety. But it sounds nice. It's got a nice ring to it."
That versatility can be a nice asset at his next destination. The coaching staff can utilize him in a variety of ways to fit any given situation.
Expecting Hall to be a lockdown defender on the outside is unrealistic, but he'd be a solid slot corner and general Swiss army knife in the secondary.
Hall's experience will also be welcome in a somewhat unproven group of defensive backs in the Bay Area.
Dontae Johnson has started 11 games over the past four years, while Rashard Robinson is still finding his footing in his second season.
More so than helping improve San Francisco's pass defense, Hall's biggest task may be aiding in the development of the Niners' young cornerbacks.