Johnson's four-week injury adds to star-studded Cronulla casualties

Cronulla's multi-million-dollar casualty ward is at standing room only with Shaun Johnson the latest Sharks star copping a long-term injury.

Johnson will be out for the next month with a torn hamstring picked up in Saturday's loss to Brisbane.

The Kiwi international joins fellow big names Matt Moylan (hamstring), Aaron Woods (fractured foot) and Wade Graham (ACL) in the stands for Cronulla, amounting to almost $3 million of sidelined talent.

The prognosis on Josh Dugan is at least a positive one for coach John Morris, with Dugan pushing to be fit for Friday's short turn around against the Storm.

The ex-NSW Origin centre was a late withdrawal on the weekend with a hamstring injury, but scans have confirmed he has not done significant damage.

Briton Nikora will also return from suspension against the high-flying Storm, with all hands on deck as the Sharks defeat to the Broncos drops them back out of the top eight.

Johnson's latest blow continues a tumultuous trot in recent times for the 28-year-old, who has battled a groin injury as well since his messy exit from the Warriors landed him in The Shire.

A four-week lay-off will keep him out until at least Cronulla's round 11 local derby with the Dragons in Wollongong.

Moylan is scheduled to return a week earlier against Manly at home, while Graham is expected back after the Sharks' round 12 bye.

Johnson is also expected to be cautioned by NRL officials, but not face further punishment, for using his phone in the Suncorp Stadium sheds after coming from the field.

It's understood Johnson was calling his fiancé to assure her he was OK after copping the injury, with the Sharks half apologising for flouting NRL dressing room protocol.