The Blues were rocked hours before their departure for Adelaide on Monday when Mitchell told his teammates he would sit out the series opener with a calf injury.

Scans showed Mitchell, 25, had suffered a grade-one strain, meaning he should be fit to feature in Game II at Brisbane's Suncorp Stadium on June 21.

Fittler also laughed off fears that an infected wisdom would impact star halfback Nathan Cleary for Wednesday night's opening game at Adelaide Oval.

But the NSW coach conceded the late loss of star centre Mitchell, who missed all of last year's series with a hamstring injury, would impact the Blues' ability to intimidate the Maroons.

"There was a chance he could've come down and trained and possibly felt better," Fittler said after the Blues touched down in Adelaide.

"But he made the unselfish decision to allow Stephen to take his position.

"Stephen had been there all week (as 18th man), I think he felt that was better for the team.

"He was very emotional, it shows where he is at, at the moment, he wants the biggest stage and it's disappointing for everyone.

"A lot goes with Latrell and it's a shame we don't get to see him playing State of Origin, I'm sure he'll be right for game two."

Crichton will be thrust into NSW's left centre spot but he should feel at ease playing there given he will be on the same edge of Penrith teammates Jarome Luai and Brian To'o.

Canterbury five-eighth Matt Burton takes Crichton's role as 18th man.

"When I got the call for 18th man I knew I had to be ready for anything," Crichton said.

"I've prepared as if I was starting so if anything like this happens I won't be looking back and think I should've done this or I should've done that.

"Now that the opportunity is there I'm keen for it and ready to go."

Fittler said he had no concerns throwing Crichton into the mix after he featured in all three games of last year's series.

"He's played in big games, he's been in grand finals and won grand finals and did a good job at the World Cup (with Samoa) and with us," Fittler said.

"He won't be overwhelmed by the situation. We had a move called 'Latrell' so Stephen might have to adjust to that."

Fittler said he had no fears about Cleary's infected tooth.

The Penrith halfback won the 2021 premiership while playing with a labral tear in his shoulder through the back half of the season.

"He's had it (the tooth issue) for months, so there's no problem and he'll play and there was never a problem that meant he wasn't going to play," Fittler said.

Australian Associated Press