Coach Steve Borthwick selected Vunipola as his only specialist number eight in their 33-man squad for the World Cup but has been forced into shuffling his pack.
Vunipola was sent off in last weekend’s defeat in Ireland and handed a ban that means he also misses England’s World Cup opener against Argentina in Marseille.
England captain Farrell will be banned for the opening two matches of the World Cup after this week receiving a backdated four-game suspension.
He was sent off in the 19-17 win over Wales at Twickenham on August 12th but initially had his red card overturned before World Rugby appealed.
England left him out for last Saturday’s clash in Dublin with Ford taking over and Farrell's long-serving deputy will play again against Fiji, England announced on Thursday.
Earl got the nod over Lewis Ludlam for Saturday’s lineup and a chance to solidify his chances of playing in England’s opening Pool D clash.
He will have support from Jack Willis at openside flanker and Courtney Lawes on the blind side.
Lawes will win his 100th cap in the clash with the Pacific islanders, who last week provided World Cup hosts France with a tough examination in Nantes.
“Fiji have proven themselves to be a strong opposition and we look forward to what we expect to be an exciting and challenging game,” said Borthwick in a statement naming the team.
“Rest assured that we will be looking to convert the opportunities we have recently been creating week-on-week into points on the scoreboard."
There are nine changes to the side that started against Ireland with Theo Dan getting his first England start at hooker.
England team:
15. Freddie Steward, 14. Max Malins, 13. Ollie Lawrence, 12. Manu Tuilagi, 11. Jonny May, 10. George Ford, 9. Alex Mitchell; 8. Ben Earl, 7. Jack Willis, 6. Courtney Lawes (captain), 5. Ollie Chessum, 4. Maro Itoje, 3. Dan Cole, 2. Theo Dan, 1. Ellis Genge
Replacements: 16. Jack Walker, 17. Joe Marler, 18. Will Stuart, 19. David Ribbans, 20. Lewis Ludlam, 21. Danny Care, 22. Marcus Smith, 23. Joe Marchant
