Farrell on the bench for Lions against Australia-New Zealand
The former England captain is set to end a period in the international wilderness as the Lions continue their nine-game tour with their fifth and final warm-up on Saturday.
Farrell made the dash to Australia last week after being summoned as cover when utility back Elliot Daly broke his arm.
The 33-year-old, on his fourth Lions tour, earned the last of his 112 Test caps at the 2023 World Cup, and is coming off an underwhelming and injury-plagued season with French club Racing 92.
"He's (Owen Farrell) the same as everybody else who has had to get up to speed pretty quickly," coach Farrell said.
"I think the art at this stage of the tour is mentally being as switched on as you possibly can.
"There's not much training that you can do. We're at a captain's run tomorrow and that's the preparation for this game.
"All the other learnings are from the video of the games and that's the nature of where we're at."
The Lions are unbeaten in four matches in Australia after wins over four Super Rugby sides, including 36-24 against ACT Brumbies on Wednesday in Canberra.
But they endured a sloppy performance against the Brumbies, with notable issues around the breakdown.
Numerous changes
The Lions have revamped their line-up with Tadhg Beirne to take the captaincy reins, with Maro Itoje sitting out the game.
Young star Henry Pollock returns having withdrawn from Saturday's 21-10 victory over the NSW Waratahs as a precaution with a tight calf.
Scrum-half Ben White will make his first start on the tour for the Lions and will link up with Fin Smith at half-back.
Scottish duo Sione Tuipulotu and Huw Jones will form a potent combination in the midfield.
Ireland fullback Hugo Keenan, who has been plagued by injury and illness so far on tour, will have a chance to impress with Blair Kinghorn sidelined after limping off against the Brumbies.
"I don't think it's as bad as what could have been," Farrell said of Kinghorn.
"It was something innocuous, a rugby accident that was unfortunate. Fingers crossed we get good news."
The Australia-New Zealand side, the first time the powerhouses have joined forces since 1989, will be led jointly by David Havili and Lukhan Salakaia-Loto.
Coach Les Kiss picked 17 internationals in his matchday 23 for Saturday's final warm-up game for the Lions before they face Australia in the opening Test on July 19 in Brisbane.
"We are in a great position just over a week out from the first Test," Farrell said.
"The players now have another chance to put in a strong team performance and put a hand up for selection for the Test matches against the Wallabies.
"Les Kiss has assembled a strong squad with lots of international experience and we know that he will have them well organised and they will bring a lot of physicality to the contest.”
British Lions XV (15-1):Hugo Keenan; Mack Hansen, Huw Jones, Sione Tuipulotu, Duhan van Der Merwe; Fin Smith, Ben White; Ben Earl, Jac Morgan, Henry Pollock; Tadhg Beirne (capt), James Ryan; Will Stuart, Luke Cowan-Dickie, Pierre Schoeman
Replacements: Ronan Kelleher, Andrew Porter, Finlay Bealham, Scott Cummings, Josh van der Flier, Alex Mitchell, Marcus Smith, Owen Farrell