Reports seem to now say it was corks on both knees and that he was in doubt with a bad groin. From nrl.com:
Manly skipper Ben Kennedy, who limped of with corks in both knees in the 77th minute, revealed he had hardly trained with the side in the past two weeks because he was carrying a groin strain.
But Kennedy, who is trying to get his body through one last NRL season, said he would not be sitting out any matches to freshen up.
"I think we've only got two more games before a bye, they're very important games for us," Kennedy said.
"We've set some personal goals and we're trying to achieve them."