It never made sense to move the 33-year-old defensive end to a standup position in which he'd have to drop in coverage in certain formations.
Now that he's been traded to the Carolina Panthers, Allen can dispel the party line and admit he was never going to work as an outside linebacker.
"That's just where I feel comfortable," he said of the move back to defensive end, via the Charlotte Observer. "I understand the game with my hand on the ground. I feel like I can play faster, stronger. I have better leverage, I have better technique. This is where my heart and my home is, in a 4-3 defense."
He added: "I don't have a bad thing to say (about Chicago). I just -- I'm not a stand-up 3-4 guy. I gave it the old college try."
The NFL's active leader in sacks should inject some life into a Panthers pass rush that has been hammered by injuries. While he's not the every-down, dominant force he was four years ago, Allen certainly can bring pressure in spurts.
"That's just the coolest thing ever," he said. "To go from last to first, you can't help but smile."