I think its clear he's a DH moving forward but I don't the bat has declined nearly as much people think. His hard hit rate is actually higher than it was and he's making more contact with pitches in the zone.
His value probably even increases as a DH considering how bad he's been in RF. I think I'd much rather have him back on a 1 year/$20 Million or 3 year deal and take the draft pick from Edwin than sign Edwin for 5 years.