Manly are counting the cost of their opening round NRL 18-6 defeat to Melbourne, with injuries to Jamie Lyon and William Hopoate and Jason King being placed on report.

Former Test centre Lyon suffered a hamstring tear while joint skipper prop King was put on report for lifting his knee as he ran into Storm tackler Cameron Smith in the 64th minute.

Hopoate damaged his AC shoulder joint and managed the complete the game, but expected to be sidelined for up to six weeks.

All three could miss next Sunday's clash with Sydney Roosters at the Sydney Football Stadium.

Lyon walked from the field just before half-time and didn't appear to be in any pain, however coach Des Hasler said the injury was believed to be serious and he could spend a month on the sidelines.

"He's the biggest concern with a hamstring, he'll need scans to know to what extent that it's torn," Hasler said.

"It's a significant blow, particularly with the points Jamie can score. He's a potential match-winner every time he touches the ball and it appears he'll be laid up for some time."

King's surge into Smith was picked up when a possible try by Manly centre Tom Williams was investigated by video referee Bernard Sutton, who denied the four-point effort.

Hasler wasn't too positive about the likelihood of having King available for round two.

"Obviously it's what they consider to be a knee lift," he said.

"We'll have to have a look at it and go from there.

"I don't think his carry-overs are too dusty."

In Sydney, the Roosters opened their campaign with a 40-29 over South Sydney on Friday and Hasler said his team would have to improve dramatically to compete.

They let themselves down with a poor completion rate, their lack of ball control in the second half repeatedly handing the Storm possession and territory with Hasler describing their attitude with the ball as "inexcusable"..

"It was a tough night for us, we need to regroup and regather because we're coming up against a very good Roosters team next week," Hasler said.

In a further blow for the Sea Eagles, backrower Shane Rodney's return to action from the knee injury he sustained last season, ended in misery in a NSW Cup match against Western Suburb.

The former Penrith star dislocated his collar bone and is expected to be sidelined for six weeks.

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