Here's what Pride of Detroit had to say about the pick:
Cornerback is perhaps the position of biggest need for the Lions. Depth isn't great, and with the CBA in limbo it's unclear if free agent Chris Houston, the Lions' top CB last season, will be restricted or unrestricted. That means it's unclear if the Lions will be able to re-sign him, so I felt it was important to add talent to this position both as an insurance plan for Houston and to make the position better in general.
I feel like the Lions got great value with both their picks so far. Bowers dropped a little in the first round because of the knee issues and there are some who feel Harris could be a first round pick in the draft. This is a solid draft for the Lions.
For the full explanation of the pick, check out Mocking The Draft.