The 33-year-old former Cat hurt the thumb on Thursday, married his long-term partner Erin Briggs on Friday and will have surgery on his left thumb early next week.

In a statement on the club's website, Giants general manager of football Wayne Campbell said the injury was a setback for Johnson's pre-season program, but he would be ready to play in round one.

Johnson's thumb will be in plaster for the next six weeks.

"This is certainly one of the more unusual injuries but Steve is a professional and coming into his 16th pre-season, we have no doubt he knows how to get himself ready for the season proper," Campbell said.

"While he won't be able to participate in full training for a few months, he'll still be able to work hard on building his fitness base throughout the pre-season."

Johnson spent 14 seasons at the Cats before joining the expansion club on a two year contract, with the first year in a playing capacity, and the second either playing or coaching.

There was some doubt about whether the Giants, a rapidly improving team blessed with plenty of young talent, would keep Johnson as a player for 2017, but his 43 goals in 22 games this year showed he was still capable of performing at the highest level.

He missed GWS' preliminary final loss to the Western Bulldogs through suspension, but GWS signed him as a player for a another season following that defeat.