A walk-up starter for the Blues, South Sydney centre Mitchell tweaked his recent back injury and could not finish Friday night's loss to the Dolphins at Magic Round.
Despite his fitness cloud, the in-form 28-year-old is likely to be selected on Laurie Daley's team sheet come Monday morning and operate under a customised training schedule.
Payne Haas and Brian To'o were in the same position at points during last year's series and finished as the Blues' best two performers of 2025.
The newly-expanded six-man bench will mean there is cover for Mitchell in camp should he need to sit out of sessions.
Parramatta winger Addo-Carr was optimistic about Mitchell's chances of lining up for the series opener at Accor Stadium on May 27.
"I spoke to him after the game. He said he was all good," Addo-Carr told AAP.
"He's one of the best in the world, so hopefully he puts the Blues jersey on."
Zac Lomax's code switch and injuries to Jacob Kiraz, Tom Trbojevic and Mark Nawaqanitawase have left the Blues short on elite wing options for Origin I.
But Addo-Carr is considered a leading contender alongside Penrith ace To'o.
The 30-year-old has revived his career since joining the Eels in 2025, earning selection in all three matches of Australia's 3-0 Ashes whitewash last year.
Addo-Carr did not score a try in the Eels' 34-8 loss to Melbourne on Saturday night but came up with two big defensive plays.
He mowed down Storm speedster Moses Leo and forced the ball from his grasp following a 60-metre tear, then ankle-tapped Sua Fa'alogo just as the fullback appeared certain to score.
Addo-Carr's efforts would not have gone unnoticed by Daley and his staff.
"Just trying to be in the picture. I'm disappointed with the result, but," Addo-Carr said.
Two-time premiership winner Addo-Carr last featured for NSW in 2023 but still felt he had more to give at Origin level.
"I definitely want to put my hand up for it, that's for sure," he said.
"If Laurie and the leadership group want me to do a job for NSW, I'll definitely put my hand up and give it my all."
The second wing spot is one selection quandary facing Daley.
After the final day of Magic Round, the coach will need to determine whether to hand the fullback spot to incumbent No.1 Dylan Edwards or former Blues captain James Tedesco.
Jackson Ford, Addin Fonua-Blake and Ethan Strange are among those considered in the frame for Origin debuts.
A wealth of talent also leaves Daley to consider which two of Hudson Young, Haumole Olakau'atu, Angus Crichton and Jacob Preston should be starting in the second row.
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