The Warriors have been written off in the countdown to the NRL finals after Johnson broke his left ankle while scoring a try during the 32-12 loss to Manly in Auckland.
The in-form No 7 is ruled out for the remainder of the year, leaving a gaping hole in the play-making ranks of the eighth-placed Warriors, who host the sixth-placed Sharks on Saturday.
A day after undergoing surgery, Johnson said he was disappointed Warriors fans had cast doubt on the club's top-eight bona fides.
"I don't want anyone to think that just because I'm out, the season's over," Johnson said in Warriors website video filmed in his Auckland hospital ward.
"We've got a real quality squad and we've got a bit of depth and a coaching staff that has managed that well.
"The weekend was a setback for us but with the players that we've got, they won't settle for anything less and I just hope we can all stay behind them. I'm really upbeat about the remainder of the season."
The 24-year-old broke the fibula bone and partially dislocated his ankle when his leg was jammed beneath the weight of Manly second-rower Tom Symonds.
A plate has been inserted, held in place by two screws, which medical staff have was likely to stop Johnson from running freely for four to five months.
That diagnosis has already stoked Johnson's competitive fire.
"There's a little challenge. I want to beat that time and just get moving as soon as I can," he said.
"But obviously I want to be smart about it. I don't want it to be an injury that hangs over me for the rest of my career."
Johnson says the first major injury setback of his career will be a test of his character.
He says he will find it hard to watch the Kiwis' end-of-season tour of England.
