Jon ain't what he used to be, speed-wise.
Jon's striking defense is also not the best. I think Pereira's got a real shot in that. I'd love to see him fight 15 lbs heavier. He'd sure have to change his style to beat Jon, though. He's gotta move his feet a LOT more. I think he's got that in him, it's just not usually in his interests to give away the attack.