The AFL has confirmed Sydney speedster Lewis Jetta should have been penalised for running too far without bouncing in the lead-up to his showstopper goal in last Friday's preliminary final.

Jetta took just three bounces while sprinting 80-100 metres, with the rules stating a player must bounce after every 15m.

The league's umpires boss Jeff Gieschen confirmed to the AFL website that Jetta broke the rules and his incredible goal shouldn't have counted.

"We are more than not sure - we are very sure (he did not take enough bounces)," Gieschen said.

However the rule is enforced with noted leniency, as the pace of the game makes it incredibly hard for officials to judge the difference between 15 and 20 metres.

"The umpire on the night does not have a tape measure, he makes a 'guestimate' of how far he has travelled," Gieschen said.

"It happened very quick. In reflection, when we sit down and review that, he has run too far."