I would hold for now. I think this year he'll get more exposure and his hobby value will increase. #52 on NFL top 100 as a rookie. He's a beast but, despite being NFL Def ROY, he doesn't have the street cred of a Clay Mathews just yet.
I'm expecting his play to continue to rise this year. Manning will certainly help his value. Teams with high powered offenses force the opposing offense to pass more, which gives more opportunities for sacks and ints.
Look for him to pop in value around mid-season. I would say hold for now but sell when that happens. Once the hype hits, his card values will peak. While most defensive players' cards don't have as much value as offensive guys, they can still go up in value once they get a little buzz.