Granted, I was making some chili paste a couple hours ago and some splattered into my eye, so NOTHING is clear at the moment. However, I'm not sure this is as clear as you state. His defense has tailed off to the point where he can't handle the position. The defensive grades on Fangraphs stand out like a sore thumb.
So with Turner, you are likely looking at a DH. He would be an upgrade on Miguel Cabrera, but with a crowded outfield, you are likely sitting one of Canha/Greene/Carpenter to get Turner in the lineup, and I'm not sure that is much of an upgrade, if at all, especially once you factor in the steep decline from age 38 to 39. (For what it is worth, the Prospectus defensive metrics had Turner above average last year. Savant is in line with the Fangraphs numbers).