I think the Twins should move Kepler because they have a pretty good player in Kiriloff coming up and Cave and Wade could hold down the corner until he's ready.
Kepler has been a pretty steady 2-3 WARish player in the corner while making some improvements but still having a really low babip. If his babip were normal, his stats would look a lot better. Some team might really be willing to bet on him making that jump. He's also under team control for four more seasons (through his age 29 season).
In Colorado both Carlos Gonzalez and Parra are both free agents. David Dahl will take over for one of them but they still have an opening in a corner and probably still have a window in the tough AL West. They have a lot of young arms - Freeland (super stud), Marguez, Anderson and Gray each threw at least 170 innings and Peter Lambert (#99 on pipeline) got to AAA last year. Former top prospect Jeff Hoffman spent most of last year in AAA and didn't look great in the PCL. Gray's stats weren't great at first glance and he was actually sent down to AAA at some point. He was left off the NLCS roster after the Cubs hammered him in the wild card game. Is there a scenario where a Kepler/Gray swap could happen? Gray will be 27 next year.
Kepler and Gray have both been worth exactly 7 bWAR the last three seasons. Kepler has one extra year of control. Gray probably has higher upside but at 27 it's worth asking if he's got anymore improvement left.