The way I look at it is if we trade Duran we are likely upgrading our roster/defense but downgrading the lineup.
It's not that Duran is bad at defense, it's just that the guys you mentioned are so good, and he would bring back value (Ideally) up the middle in the infield. But you're also subtracting him from a lineup that already needs addition not subtraction.
Of course, this is all avoidable by just keeping him. It's perfectly plausible to DH him and/or rotate him between DH/OF and trade pitching for an infielder. This does create a roster dilema with Yoshida, but we are kind of there with him already so its like.....whatever.
Despite the roster crunch, I kind of like the ideal of keeping all 4 outfielders. The concept of trading a 4-5 War outfielder for a 2-3 war infielder doesn't sit well with me, even if that means we should command more than just a Paredes (type) in a trade.
It might make sense, to trade Duran for prospects, and put together an entirely different package for an infielder (assuming you still need to move an OF),