"We are comparing an aging 1B with a bad back (Coming from the off season) with two and half years of OPSING around .700 with a young healthy Thames, who continues to show potentiol with the bat, and is already OPSING a hundred points higher."
The concept of Thames playing first should not be based on whether or not he would be better than Lind, it should be based on whether it's a good idea to move Thames to 1B.
Small sample size aside, Thames is out OPSing Lind this season by about 60 points, not 100. This does not mean that Thames is hitting well, it means that Lind has been awful. Lind has played well defensively at 1B. Thames (as far as I know) has not had any meaningful time playing 1B.
Thames is not an embarassment at the plate, but he has been in the field so far. Any potential in his bat is only valuable to us in a role where he doesn't subtract value with his horrible defense.
Thames' current OPS is .718. How much higher does it have to be to make it worth living with him in a defensive role?