Since Reggie Hayward went down with a season ending injury, the team has tried to make a 3-4 defense work in Duval. This has resulted in mixed results as the Jaguars have attempted to make their personnel fit the scheme. Derrick Harvey is one of the catastrophes of this misshapen method. He's been forced to take on a role this year that is altogether unfamiliar territory, the role of a 3-4 LB.
Derrick is regularly on the end of the line, standing with his hand off the ground, prior to the snap. Sometimes he rushes the passer, and others he drops into coverage. He's a very awkward looking coverage LB, and seems best fit only in a zone coverage scheme. I shudder to think of him covering a TE or RB on a regular basis (which I've seen him do before, albeit with some success). His lanky frame does seem to cause some issue for opposing quarterbacks when the team uses a zone-scheme. I've noticed Derrick is steadily becoming better at disguising whether or not he's going to rush the passer or drop into zone on any given play. That's a major improvement, and it is a key component to any rushing LB's repertoire. You must be able to disguise your blitz.
This is clearly a man who is built to be a 4-3 defensive end, and some of his struggles rushing the passer may have to do both with his lack of opportunities, and the position switch. He was improving steadily towards the end of last year, and he seems to be playing well this year (especially against the run). I wouldn't call him a bust, but I don't think he'll be the player we drafted him to be as long as he's in a 3-4 scheme. It's clearly stunted his development as a pass rusher to learn new responsibilities. He may still be a great rush LB, but it may take more time for him to develop and get comfortable in his new role.
I also notice that our Nickel defensive line includes Harvey, Groves, Landri, and Ingram (or Smith). That's not a bad pass rushing line, and I've noticed Harvey seems more comfortable operating out of that front, at least it appears so to me. Pressure is the key to fixing the atrocious pass defense. Our secondary is serviceable, and if we could get some pressure, we'll see even more interceptions.