Sika Manu won't be back to ease Melbourne's prop shortage anytime soon with the New Zealand international suffering ongoing problems with his badly broken leg.

Manu had a rod inserted last July when broke both the tibia and fibula in his left leg playing against St George Illawarra and thought he was on track for an early season comeback when he started running in January.

But the 22-year-old was forced to put those plans on hold when he developed sharp pain in his knee.

"When I walk I get a sharp pain in my knee from the time I wake up until I go to bed," Manu said.

"I'm not too worried, I'm just trying not to push it to let it heal properly."

The powerful backrower was in top form before the injury with the Storm using his bullocking runs up the middle to generate attacking momentum.

He was also only behind Dallas Johnson, who has left to play in the Super League, and skipper Cameron Smith in average tackles made.

Manu will have weekly extracorporeal shockwave therapy for the next month in a bid to ease pain in the tendon underneath his knee-cap.

It's believed that the shock waves create new blood flow into the area.

Storm physiotherapist Kieren Morgan said if it wasn't a success Manu could have surgery to have a nail removed, which could be causing the knee irritation.

He has already had screws removed from his ankle, which were causing problems.

"It could be related to the rod or from over-use from his running so the plan is to hit it with everything that we can do and hopefully it will start to come good again and then we can start to talk about when he can play again," Morgan said.

Morgan was confident Manu would make a full recovery and be back playing midway through the season.

Melbourne will start the season next Saturday night against Cronulla without premiership props Brett White and Ryan Tandy, who both underwent off-season shoulder surgery.

Brought to you by AAP © 2024 AAP