With the shoulder injury I’m not sure Frelick can play 3B even in an emergency. Right now his throws have no power behind them. It’s bad for a RF it would be a colossal mistake to put him at 3B with that weak arm.
If his throws don’t improve you have to move him to LF and that is already occupied by a far better player both offensively and defensively considering Sal’s arm is basically a pool noodle.