Two things we know about the Raiders right now: Jon Gruden is a quarterback guru and the Raiders have one in Derek Carr. Those are established facts. Gruden has several times said Carr was one of the major factors that drew him back to coaching the Raiders.
It would be interesting to see what Gruden would do in this draft should he have a need at the position. In such a scenario, barring any kind of trade up, the best quarterback who would likely be on the board at that time would be former Heisman Trophy winner, Lamar Jackson.