From the outside, this appears to have come out of the blue given Jacko was named in the squad for this week. Interesting to find out if his body broke down again during training and that triggered the sudden retirement(?).
Anyway, all the best to Jacko in his post-footy career. He was the last of our stack of 2003 draftees (most didn't last long aside from himself and Tucky). So for pick 53, he's done well to survive for 11 years at AFL level, play 156 games to become a RFC life member and win a B&F in 2013.