PFF's ratings are based on stats. How can you expect them to give a high grade to someone who's been injured last year? They're not gonna invent some training camp, recovering-from-injury metric just for something like this. I trust these guys -- their evaluations are certainly more justified than the regular fan's.
If it was just based on stats they wouldn't have graded Cam and Tannehill the same.
I do like PFF and usually value their stat systems. This time, however, I think there is less value in what they're saying. And I'm not even just complaining about what they said about some Panthers. Like someone pointed out above, if Jimmy Graham isn't an elite TE who the hell is?! A fully healthy Gronk is the only TE that's better than Graham today. Which means Graham is the best and will probably be the best for a while to come. And rating Dwan Edwards the same as Nakamura is a joke. Dwan was bad in run defense, but good in pass defense. In every aspect of the game, Nakamura was worse than Dwan's worst aspect.