The 32-year-old former Hull KR hooker made his first start of the season in last week's Super League defeat by Wigan and is guaranteed to keep his spot against Catalan Dragons with the club's other specialist number nines both injured.
Fisher, who played for the Dragons in 2012 and was in their side that demolished the Broncos 42-18 at the Etihad, joined the Londoners' backroom staff in the winter as assistant to head coach Tony Rea but was also intent on continuing his playing career.
Fisher not only feels he can still cut it in Super League but is determined to play for Scotland in the end-of-year World Cup and knows he needs to maintain his match fitness.
"It was always the plan for him to play," said Rea. "He wants to go to the World Cup with Scotland so he was never going to not play but I've definitely used him more than I thought I would."
With first-choice hooker Chad Randall sidelined with hamstring and groin injuries and back-up Tommy Lee facing a six-week lay-off with a knee injury, Fisher can expect plenty of game time against his old club on Saturday.
Rea is set to give a debut to 20-year-old half-back Mike Bishay, who has been playing on dual-registration with Championship One club Hemel Stags, but will keep changes to a minimum.
The coach had threatened to swing the axe following his side's 64-6 mauling by Wigan, claiming "tough decisions have to be made", but he believes he over-reacted immediately after the game.
"I was a bit hard on us," he said. "When I looked at it closely, Michael Robertson pulled out overnight, Dan Sarginson in the warm-up and Fisher got hurt early so we had to adjust.
"A lot of stuff happened which, in hindsight, didn't put us in a good light. We already had a few out and they just got us in those spots. The team was put under pressure by not being able to prepare for some of the things we needed to prepare for in a game like that."