He did a full pre season with the club before heading back. This is when he joined the club. He had the same pre season grounding as every other 2007 draftee.
Which means nothing as Dangerfield has done 3.
He is almost a year younger than most of the draftees in his year. The current AFL drafting rules would actually make him ineligible for the draft he got drafted in if it happened now.
So as far as physical maturation you should probably be comparing him to 2008 draftees as he is much closer in age to them.
That is why he was left in school for the year. His age meant we were not losing a year of his playing career keeping him in school.
His game's greatest strength is his strength so I do not think it is particularly unfounded for us to expect more out of him after a few more pre seasons (years).