Farrell set for 'challenge' of downing Bordeaux in Top 14
The 32-year-old, who joined the Paris club in the summer after parting ways with boyhood club Saracens, was pulling the strings during Racing's opening two games and is again set to pull on the number 10 jersey.
"Why would I rest him?" Lancaster said at a press conference on Tuesday.
"We've got a small squad this year. We want to rotate because it keeps motivation high but equally we want to win every game. Will Owen play and start all 26 games? Probably not. But he's an excellent player and wants to play rugby.
"He's just getting started in France so it's early for him. I know he wants to get into a rhythm."
Farrell has not had an easy start.
Racing lost their opener at Castres when they conceded a last-minute try and even though they came through to beat Clermont last week, the Englishman suffered an off day with his normally reliable boot and also picked up a yellow card.
"He has a lot to deal with," said Lancaster. "All kickers have noticed a change with the 60-second rule after tries. It's tight and a lot of his kicks were from the sidelines.
"He received a yellow card but that was for the team. It was the team's penalties that put us in that position, it wasn't Owen."
Racing will need to bring their A-game if they are to upset last year's runners-up in the primetime Saturday night slot.
"Going to Bordeaux is one of the hardest challenges in the Top 14," said Lancaster.
"The quality of the team, the quality of the coaches, the environment that's created. It's going to be Saturday nine o'clock.
"So we need to be cool in the head but we need the intensity to match them."
Bordeaux won their opener against Stade Francais but frustratingly lost to a penalty after the hooter at Lyon.
Former Ireland fly-half Joey Carbery will be missing from the Bordeaux line-up after injuring his hand in that game but France outside half Matthieu Jalibert will make a more than reasonable replacement.
Hogg 'problems'
Champions Toulouse top the table - one of only two teams along with Lyon to have won both games - but they will face a difficult test at rejuvenated Montpellier, the 2022 champions who came close to relegation last season.
Former Scotland captain Stuart Hogg missed last week's win at Perpignan after allegedly breaking his bail conditions in Scotland but Montpellier head coach Joan Caudullo intimated that he would be available for selection this weekend.
"You get the impression that as soon as he returns to Scotland, he's in trouble," said Caudullo. "But today, he's part of our team, our family. His problems are our problems too."
Another English fly-half Joe Simmonds, who has just signed a contract extension that will keep him at Pau until 2028, takes his side to La Rochelle where he will line up against former Exeter teammate Jack Nowell.
Pau announced this week that Hugo Auradou, one of two players charged with sexual assault in Argentina during France's summer tour, had returned to training although no date has been given for his return to competition.
The other player Oscar Jegou has also started training again at La Rochelle while Melyvn Jaminet, who was banned for 34 weeks for a racist outburst on the same tour, is back with his Toulon teammates, although not set to play until 2025.
Toulon, who edged Castres last weekend, are in action in the primetime Sunday slot at Stade Francais.
