You do give up on his potential as a rare pass rushing threat at DT, but at the same time, there's a pretty urgent need for a sub-package DE. I don't know if he's going pure LEO, but the team needed someone to play opposite Avril when Bennett shifts inside. We don't have much depth there besides Marsh, who's looked like a JAG so far.
This gives you an opportunity to play Avril, Bennett, Clark and Hill together in passing situation. There's also a lot of talk of this being a great DT class, and (whether that's true or not) that could have factored into this move. For me, I'm excited about it because I thought Clark had some potential to replace Irvin as a subpackage DE, and it looks like they're going that way.