Whom should the Oilers target in a trade of their No. 4 draft pick?

In Connor McDavid, center, Leon Draisaitl, right, and others, the Oilers have a bevy of young talented forwards to build around. Now, they just need to build up their blue line. NHLI via Getty Images

At this year's NHL draft, one of the busiest general managers could be Edmonton's Peter Chiarelli. The Oilers have acquired all the forwards they need through the previous six entry drafts, finally secured a solid starting goalie in Cam Talbot via free agency last summer, and all that remains is to obtain a legitimate No. 1 defenseman. Is their fourth overall selection just the trade bait required to fill that hole?

Statistically, this high-level question can be broken down into three components: What kind of defenseman do the Oilers need? Is there anyone suitable available through free agency? And who might be available in trade?