Kiwi sevens supremo Gordon Tietjens is uncertain if Jarryd Hayne can play sevens.
He does know if Hayne adapts and makes it into Fiji's side for the Olympics it will be a massive achievement.
"It's a tough game sevens rugby, you have to be really conditioned and you can't just go and pull out any players to jump into a sevens team and that's the challenge we have," Tietjens said.
If Hayne was going to make the Olympics he would have to play this weekend's last world series event at Twickenham.
"He is certainly a great athlete. Can he play sevens? I can't answer that."
Tietjens was surprised when he heard about Hayne's switch because sevens was a challenging sport.