Yeh. more referring to him being under-sized height wise. He was good on the ground and in the air and moved well.Reckon you're underestimating Derm the athlete. He was small for a CHF even in his time at only 186cm but the young Derm was a beautiful mover. His body paid the price for his hard man approach and he was pretty much finished by 27/28.
It's a bit like Sicily, it's staggering in many ways that he can play on some much bigger men yet is rarely beaten and often out positions his opponent. I reckon it';s all to do with identifying the ball drop a fraction earlier and positioning beautifuly. Jack was the best in the AFL at this for a lot of years.