Fisilau among new faces in England Six Nations squad
Fisilau is rewarded for his fine form for Exeter, while props Billy Sela and Emmanuel Iyogun are also selected for the first time.
George Furbank is included despite being limited to just four appearances for Northampton this season by injury.
Northampton fly-half Fin will fly with the squad for a training camp in Girona to continue rehabilitation on a calf injury.
"We've picked a squad with a good balance of experience, leadership and exciting potential," said Borthwick.
"The margins in the Six Nations are incredibly fine so our aim over the coming days is to come together quickly, prepare thoroughly, and make sure we're ready to perform.
"If we prepare well and keep demanding the highest levels from one another, it puts us in the strongest possible position when the championship begins."
Farrell has not played for England since the 2023 World Cup but is yet to close the door on a return to international rugby and played on the British and Irish Lions tour to Australia last year.
The 34-year-old had been ruled out of contention by a move to Racing 92 in France, but has since returned to Saracens making him potentially available for selection once more.
Caluori, 19, has shone for Saracens this season but misses out against tough competition for a place on the wing.
England begin their Six Nations campaign at home to Wales on February 7 before a trip to Scotland a week later.
Buoyed by victories over New Zealand, Australia and Argentina in November, Borthwick's men are looking to win their first championship since 2020.
Forwards (20)
Ollie Chessum (Leicester), Arthur Clark (Gloucester), Alex Coles (Northampton), Luke Cowan-Dickie (Sale), Chandler Cunningham-South (Harlequins), Tom Curry (Sale), Theo Dan (Saracens), Trevor Davison (Northampton), Ben Earl (Saracens), Greg Fisilau (Exeter), Ellis Genge (Bristol), Jamie George (Saracens), Joe Heyes (Leicester), Maro Itoje (Saracens, captain), Emmanuel Iyogun (Northampton), Guy Pepper (Bath), Henry Pollock (Northampton), Bevan Rodd (Sale), Vilikesa Sela (Bath), Sam Underhill (Bath)
Backs (16)
Henry Arundell (Bath), Seb Atkinson (Gloucester), Elliot Daly (Saracens), Fraser Dingwall (Northampton), Immanuel Feyi-Waboso (Exeter), George Ford (Sale), Tommy Freeman (Northampton), George Furbank (Northampton), Alex Mitchell (Northampton), Cadan Murley (Harlequins) , Max Ojomoh (Bath), Henry Slade (Exeter), Marcus Smith (Harlequins), Ben Spencer (Bath), Freddie Steward (Leicester), Jack van Poortvliet (Leicester)