A shoulder injury for Brisbane Broncos forward Payne Haas has kept him out of the State of Origin decider, which is due to be played at Suncorp Stadium in the Queensland capital on July 13.

The NSW Blues enforcer has been among the Blues' best so far this series, but will now miss Game 3, with a live decider forced by a Blues victory in Perth last Sunday.

The injury to Haas is one he has been dealing with for much of the season, with AC joints in both shoulders keeping him from reaching his maximum output at times in recent weeks.

It's understood he required painkilling injections to play Game 2 of the series, and has also missed one club game for the Broncos so far this season.

Waiting on his fitness is believed to be a big part of the reason New South Wales failed to name their squad on Sunday evening, as they traditionally do ahead of Origin games.

Instead, Brad Fittler waited until Monday morning to confirm his 22-man squad, with North Queensland Cowboys prop Jordan McLean ultimately replacing him in the starting side after being in the squad for the trip to Perth.

It's understood Haas will require two to three weeks on the sideline.

That will also impact the Brisbane Broncos. Haas would ordinarily have missed their upcoming Round 17 game against the St George Illawarra Dragons at home on Sunday afternoon anyway with selection in the Blues squad.

However, he will now potentially also miss games in Round 18 and 19 against the Gold Coast Titans and Parramatta Eels, with Thomas Flegler likely to replace him in the starting side.

The Broncos sit fifth on the competition table, two points out of the top four, but also only four points ahead of the ninth-placed Manly Sea Eagles, and with a difficult run home featuring the Eels twice, Roosters and Storm, as well as two games against the Dragons, who are currently on a streak of wins, will be desperate to rack up victories without their enforcer in the next two to three weeks.