If you'll have 5 trades left after using 2 this week, I would 100% say Hall. Yeah he might get injured but he also might not.. he did pretty well last year and you'll be a better spot than most if he does go down. It's not unreasonable to think Hall is a top 1-3 defender in the last 8 rounds and you're getting him for a genuine steal!
Since I'm in the X v Y now, Baker has looked good but he has become their Mr Fix It to a degree, his role will often change week by week depending on who is playing and who the tigers are playing. If he ends up getting moved forward his scoring will be toast.. so I guess it comes down to injury risk vs role risk.
My determining factor would be number of trades.. Hall + 4+ trades feels ok, Hall + 3 or less trades feels scary..