On the Raiders' current depth chart, Denarius Moore and Darrius Heyward-Bey are listed as the top two receivers. Moore has impressed the team enough to be listed as their top overall receiver, and with that comes a fantasy ranking somewhere in the sixth round. I wouldn't take him that high, he's a bit of a reach there. However, Heyward-Bey carries a ninth-round grade. He is an absolute steal anywhere after round seven, so don't worry about taking him before where he is expected to go.
Moore will likely command the defense's attention on passing downs, leading DHB to be matched up against the #2 cornerback. This is a mismatch, and he will be able to use his size and speed to exploit the matchup to his advantage, particularly in a three-wide set with Jacoby Ford also on the field. There is just too much speed there for the defense to account for, and someone is going to get free. Heyward-Bey, while not quite as fast as Ford, is a much bigger target and will be targeted deep early and often.
The difference between this year and last year for the Raiders is Carson Palmer. While Jason Campbell didn't have the inclination or the ability to complete the deep passes, Palmer does. While all three main Raider receivers can be viewed as legitimate deep threats, DHB is the biggest of the bunch and has the best chance to win a jump ball battle. He also has a good chance to become the team's main red zone receiving option.
Consider that last year only six players caught ten or more touchdowns last season, and two of those were tight ends (Jimmy Graham, Rob Gronkowski). There are only a few guys who can be considered legit WR1 on your fantasy team. They are: Calvin Johnson, Andre Johnson, Wes Welker, Steve Smith, Greg Jennings, Larry Fitzgerald and Victor Cruz. There is a longer list of guys who can be WR2, and DHB belongs on that list. Moore does as well, but I don't think he has value where he will have to be taken. I foresee Heyward-Bey being at the forefront of the WR2 crowd, with production similar to Roddy White and Vincent Jackson.
In an auction draft, DHB carries a very low auction value and can be had extremely late for only a few dollars. He will turn out to be the steal of any auction draft.
Prediction: 1,200 yds rec, 8 TD
Positional ranking: 13