Cronulla are expecting skipper Paul Gallen back as early as round five after positive early signs in his rehabilitation from a knee injury.

Gallen was expected to miss four to six weeks after undergoing surgery this week to repair knee ligament damage.

But coach Shane Flanagan on Friday backed the NSW Origin captain to only miss three weeks – possibly returning against West Tigers in round five – because of his work ethic and determination to get back as soon as possible.