Farrell made a successful union debut in Saracens' Guinness A League side three days ago, which represented his first competitive action following almost two years of injury strife.
And the 31-year-old is now poised to enter the Premiership arena when Saracens seek their first win of the campaign.
"We are delighted at the way Andy came through the game on Monday night, and the impact he had," said Saracens rugby director Alan Gaffney.
"He did a number of things very well, despite it being his first action for a long time.
"He has trained very hard this week, and as a result, deserves a place on the bench."
Farrell will be joined among the replacements by French star Thomas Castaignede, who has recovered from a calf muscle injury, while changes to the starting line-up following last weekend's tame draw with Bristol include call-ups for Rodd Penney, Matt Cairns, Kris Chesney and Ben Russell.