Melbourne Storm head coach Craig Bellamy has admitted he doesn't know when star fullback Ryan Papenhuyzen will be able to return.

The number one should be fit again in the coming weeks, but question marks will remain around his return to play status.

A calf problem was set to rule him out for just a week originally, but he will miss his fourth game this weekend.

Melbourne confirmed in a recent injury update that he had a minor calf strain, but didn't set a return to play date.

Storm coach Craig Bellamy told News Corp today that he wasn't sure when he was would have his champion fullback back on the park.

“When it first was happening it was only going to be a week, so I'm not quite sure,” Bellamy told the publication.

“I don't understand injuries all that well. I haven't done any PhD or whatever it is, so we just need to get on with what we've got.”

The Storm fullback, who has been replaced in the side by Nick Meaney in recent weeks which has opened up a centre spot for Joe Chan, will be dealt with cautiously by the club.

The Storm will have their eyes firmly fixed on the finals, and need Papenhuyzen at full fitness for a proper charge to the first weekend in October, but also, will not want to risk their star fullback given the enormous amount of time he has spent out of the game injured in recent seasons.