I have zero confidence in his ability to play 1st base long term, let alone 3rd base. I also have zero confidence in his ability to get to a reasonable weight (240 lbs?) and to keep it off for more than a few months.
I'm happy to see he's acknowledged he has a problem - it would be great to hear him acknowledge his hitting has also been s*** and that he needs to start taking his career seriously, put in his work, learn the art of hitting and get better.