'He's huge and was intimidating but he just didn't have much of an engine'

Melbourne believe the best is yet to come from man-mountain Pone Fa'amausili, who has more to offer to his rugby game than size.

The 23-year-old prop is living up to his giant promise this year in the Super Rugby AU after finally getting fit.

Rebels assistant coach Kevin Foote recalled seeing the 196cm-Fa'amausili for the first time three years ago weighing almost 140kg, and couldn't help but be impressed.

"He's huge and was intimidating," Foote said ahead of their Super Rugby AU clash with the Waratahs at the MCG on Friday night.

"But he just didn't have much of an engine."

Foote said the Rebels' high-performance unit, under Will Markwick, had made Fa'amausili a project with the Victorian-born forward buying in.

He's now able to play more minutes and has become a weapon for the Rebels with his big carries.

"Pone has been so professional with the way he's gone about it and has made huge sacrifices around his body, his diet and his training.

"For him to get up and play the way he's playing now is incredible and I think a lot of people in Melbourne would be really proud of him."

Fa'amausili is keeping Wallabies tighthead Jermaine Ainsley out of the Melbourne starting side and Foote said Fa'amausili could also take the step up to Test rugby if he kept working hard.

"He's got the frame for it - we've seen how the Tongan Thor (Reds prop Taniela Tupou) has come through," he said.

"Pone is such a big, strong boy who can carry and he's so dynamic.

"He's 133kg and he can move really, really well.

"The other day he looked like a hippo on ice-skates, he wasn't looking just to run over you, he was sidestepping and using his skill and footwork so I definitely believe he can go to the next level.

"It's a big step up but he has the right mentality."

- Melissa Woods