I disagree. In a year or so he could move to SS and stay at 90+ for 6 more years easily.
The only problem is DB's don't last that long. They are one of earliest retiring positions. It's your call obviously but hopefully he'll play at least 4 more seasons...
No need to defend the trade, as an owner, if I didn't like or want the trade, I would not of pulled the trigger! Kansas City is very happy with a new SS stud for 3 to 5 years and the chance in the draft to fill another spot!