You can play AH at any spot on a 3-4 front.
Fletcher has already said he's down with a 3-4 if the team goes to it.
Fredericksburg.com - London Fletcher on the 3-4 defense|Rich Campbell
"I can play in whatever defense," he said. "I feel comfortable in a 4-3, obviously. I feel comfortable in a 3-4. Whatever they want to do."