Melbourne youngster Harry Grant is in doubt for round 1 after sustaining a knee injury in a trial game against Newcastle.

Grant limped off the field with what coach Craig Bellamy confirmed as medial ligament damage, which will likely rule him out for up to a month.

“He’s done a medial so I doubt if he’s going to be ready for Round 1,” Bellamy said post-game and reported by Simon Brunsdon for Fox Sports.

“I’m not quite sure, it’s probably three or four weeks I’d think, medials usually are."

Grant is competing with Brandon Smith to cement their place as Cameron Smith's successor.

Grant starred on loan at the Wests Tigers last season and has been keen to make a good impression on his return to the Storm.