Rugby league great Peter Sterling has called George and Tom Burgess' performances in recent years a 'mystery' after they looked like setting the game alight back in 2014.
The Rabbitohs duo have never hit the same heights as brother Sam with many believing they've under performed in seasons gone by.
Sterling as perplexed as anyone as to why they haven't stepped up.
"It's one of the real mysteries, that George and Tom haven't gone and hit the heights that I think we all thought they were going to after that standout season when they won the competition," he said on Triple M .
"You just thought, here's a couple of young blokes that are on the rise physically, they are awesome, that confidence of winning a grand final under their belt, they're just going to go to a new level.
"It just hasn't happened.
"There may be injuries in there that are a concern, but I've seen enough of them.
"I don't know what's happened, because the world was at their feet and they haven't been the type of player that I thought they would be over the last one-and-a-half seasons.
"It's a mystery as to why they don't have the impact now that they were a couple of seasons ago.
"They really should be in their prime...they should be unstoppable."